The bluegrass cover band Hayseed Dixie (say it out loud) builds its entire schtick around covering classic rock songs in full hillbilly style — for example, hilarious versions of "Highway to Hell" and "Bohemian Rhapsody." Their prime example of this trope, however (and perhaps their Crowning Moment Of Awesome), is a version of the KISS song "Rock and Roll All Night" that delivers the title lyric and then bursts into a banjo breakdown.
If you had not read the title to Ned Luberecki's "Cabin of Death", you would toss it aside as stereotypical bluegrass song with plucky banjo and drawling country voice. Of course, this lasts only a few seconds until the first verses begin and goes on to tell the story of a family and their doctor dying from 'what we thought was the flu.'
If you should ever go out to our cabin,
Up among the pine trees on a hill,
You'll find a rusty shovel in the graveyard,
Dig a hole when you start feelin' ill!
Many of Old Crow Medicine Show's songs use this. As a old timey/bluegrass band, they play many incredibly upbeat sounding songs about pretty dark topics, including two songs about the wonders of cocaine, and one which has a chorus that consists of "Don't you ever let no woman, rule your mind/she'll leave you troubled and worried all the time". The majority of these are heavily based on traditionals however.
Especially notable is their "Carry Me Back to Virginia", an upbeat tune about how horrible it was to fight in the Civil War and wanting to be buried at home
This trope is common in Bluegrass, but you still can't beat "I Am Weary" by the Cox Family. Nice, soft country ballad in a major key, about a young woman who has totally screwed her life up and has come back home to die in her mother's arms. If there's a sadder topic, I don't want to hear it.
Angeline by O'Death is a cheerful enough song that builds to what would sound like a triumphant crescendo, except that it's about the funeral of a woman who starved to death after her children moved away and quit caring for her.
Rhett Akins' "That Ain't My Truck" is a peppy song...about a guy who gets cheated on and his girlfriend leaves him for her lover. How he finds out? He goes to her house and finds:
That ain't my truck in her drive
Man this ain't my day tonight
Looks like she's in love and I'm out of luck
That ain't my shadow on her wall
Lord this don't look good at all
That's my girl — my whole world
But that ain't my truck
The Bellamy Brothers have a ballad entitled "Jesus Is Coming". You'd think it's a dead-serious commentary on the state of religion in the world, given the choir backing them and the overall gospel sound, until they get to the line "...and boy, is he pissed."
"Papa Loved Mama". An upbeat country song that you could rock out to on a good day... about a woman cheating on her trucker husband and his deadly revenge on her. "Papa's rig was buried in the local motel/The desk clerk said he saw it all real clear/He never hit the brakes and he was shifting gears." ... "Mama's in the graveyard/Papa's in the pen."
"Friends in Low Places" is a rousing, peppy Bitter Wedding Speech in which the narrator (who wasn't invited) announces his intention to head to the bar to drown his sorrows. "Two Piņa Coladas" is pretty much the same concept, but taken to the islands with an upbeat Caribbean melody.
"Show Them To Me" by Rodney Carrington is a slow ballad... about asking a woman to flash her breasts at him.
Johnny Cash seemed to have had a fondness for toe-tapping up-tempo tunes for his dark and lonesome lyrics. Just think of "Folsom Prison Blues" and "Cocaine Blues".
The 1948 country hit version of "Cocaine Blues" by Roy Hogsed (one of the all time great country music names) from which Cash picked up the song is even more dissonant than Cash's: Hogsed sings it in very clean-cut, singing cowboy-type voice, and the lead instrument in his band is a perky, bouncy accordion!
From late in Cash's career, the song "The Man Comes Around" has lyrics depicting the Christian apocalypse over a fairly upbeat guitar.
As Johnny Cash goes, he was pretty much a badass on what comes to beautiful melodies and morbid lyrics: A Boy Named Sue (parential abuse and PTSD), 25 Minutes to Go (getting hanged), Mercy Seat (getting electrocuted), Green Green Grass of Home (getting executed in an unspecified way), Don't Take Your Guns To Town (getting shot by some jerkass), San Quentin (life in that particular prison), Singing in Viet Nam Talking Blues (horrors of the Viet Nam war) - you name it.
He also did it the other way in "The Man Who Couldn't Cry" which sounds quite dark and has quite depressing lyrics ... until you come to the last quarter when it becomes hilarious
Mark Chesnutt's "Going Through the Big D", like others, is a upbeat sounding song about a man getting the bad end of a divorce settlement (apparently she got the house and he got the car, and he's bitter about it).
Billy Currington's "Love Done Gone" is about a man acknowledging that a relationship didn't work. And yet it's one of the brightest, happiest country songs ever, complete with a cheery trumpet/backing vocal riff ("Ba-ba-da, ba-da-ba").
The Dixie Chicks' "Goodbye Earl". It's got a reputation for being, well, 'empowering', but seriously. Listen to it while paying no attention to the lyrics. Then listen again. The titular Earl is an abusive deadbeat, and as the narrator relates with alarming relish, he just had to die. Fairly typical for a vengeful country song, but the fact that the most joyous chorus is the part describing his wife murdering him, wrapping him in a tarp and keeping him around for kicks and giggles.
The second chorus does involve them getting rid of the body...
The music video ensures no viewer can miss the lyrical dissonance. Stars (Dennis Franz, Jane Krakowski, Lauren Holly, Adrian Pasdar act out the verses and everybody dances happily during the chorus, including "undead Earl". Subtle it ain't, but darkly comedic, sure.
While it makes sense that a song entitled "I'll Go On Loving You" would be a ballad, Alan Jackson caused some dissonance with that song by making its melody and arrangement very similar to "Suicide Is Painless".
Toby Keith's "Somewhere Else" is rather upbeat for a broken-hearted "lonely man in the bar" kind of song.
"Gunpowder and Lead" by Miranda Lambert sounds like a normal country song... then you get to the chorus:
I'm going home, gonna load my shotgun Wait by the door, light a cigarette He wants a fight — well now he's got one And he ain't seen me crazy yet Slapped my face and shook me like a rag doll Don't that sound like a real man? Well, I'm gonna show him what a little girl's made of Gunpowder and lead
Then, if you still haven't gotten the message, the song ends with a shotgun blast.
Just about every song by the Mavericks is about heartbreak... but they're so happy and uptempo, Tex-Mex and Cajun inspired tunes. A particularly egregious example is "All You Ever Do Is Bring Me Down".
Martina McBride's "Beautiful Again" has a cheerful melody, but the verses tell about a girl's rough childhood and teenage pregnancy. Then the chorus is about optimism in the face of everything else:
"But when it rains The past gets washed away and then She smiles 'cause she knows in the end The world gets beautiful Beautiful again"
"Independence Day" has a triumphantly patriotic-sounding chorus, and it is a favorite among conservative pundits and politicians. The song is about a girl whose parents' abusive relationship ended in arson/murder/suicide on the titular holiday.
Similarly, "A Broken Wing", about an emotionally abusive husband/boyfriend, has the same empowering feel as "Independence Day" with an empowering chorus, but in the last stanza, it talks of how her boyfriend went to the bedroom to find "a note and the curtains billowin' in the breeze" after she didn't come to church. Though it could be that she just left, the feel of the lyrics indicate she committed suicide to escape her abusive relationship.
Tim McGraw's "Just to See You Smile" is on a similiar thread. It has been used in romantic cards and has a peppy feel, but it is actually a sad song. The narrator goes on about how he would do anything to make his love smile...including letting her go to be with another man.
David Nail's "Red Light" is a song that if you take out the lyrics the melody is rather upbeat and jaunty. Then you listen to the lyrics and you discover it's a break up song. The song's lyrics don't even sound like a stereotypical break up song and while sad they lampshade it
It ain't the middle of the night It ain't even raining outside It ain't exactly what I had in mind For goodbye.
Gram Parsons' "Still Feeling Blue". Sounds very happy and upbeat but the whole lyric is about how sad he is that his girlfriend has left him and that he is going out of his mind and don't know how he'll ever live without her.
Marty Robbins's "El Paso" is an uptempo, initially sweet-sounding song narrated by a guy who dies of gunshot wounds in the final stanza. The Grateful Dead gleefully covered this many times in especially bouncy, jaunty live versions.
Darius Rucker (yes, the same guy from Hootie & the Blowfish) seems to be incapable of putting out a single without an upbeat melody, no matter how unfitting it might be. "Come Back Song" is an excellent example, being an upbeat ditty about how crappy the guy's life was since he left his girlfriend. He's also almost smiling in the videos.
Sawyer Brown's cover of "The Race Is On" is a catchy, toe-tapping tune about a brokenhearted man who feels that he's lost everything now that is girlfriend has left him.
Doug Stone's "Addicted to a Dollar" is probably the most upbeat song you'll ever hear about being broke ("I'm addicted to a dollar that ain't worth a dime").
George Strait's "Cowboys Like Us" is a rather slow waltz... about how cool it is for him and his buddies to ride their motorcycles to Mexico.
Like many of the examples here, "One Blue Sky" by Sugarland also has a happy, upbeat tune. The song is about a huge flood throwing a small town into panic.
Shania Twain's song "Whose Bed Have Your Boots Been Under?" is a really peppy song about a woman accussing her boyfriend of cheating on her and naming all of his paramours.
John Denver's "Please, Daddy" is a jaunty little holiday tune...about a little boy begging his father not to get drunk and beat his mother. Alan Jackson's remake makes it even more peppy, disturbingly.
Ray Stevens has several, but one of the more notable is "I'm Kissing You Goodbye," which is a very bouncy upbeat song about how the singer is breaking up with his girlfriend for cheating on him.
But one day I came home early, the very next week, Found a man in my closet said he was playing hide and seek Well I may be stupid, but I think I understand Why he was playing hide and seek with all his clothes in his hands
Doug Supernaw's very upbeat hit "What'll You Do About Me" generated controversy for its lyrics, which describe the narrator's plans to get revenge on his two-timing lover in a violent manner.
Jimmy Buffett's "He Went to Paris", has a melancholy tune and some grim lyrics there in the middle (wherein the singer talks about a man who lost his wife and son and one of his eyes in the London Blitz) until you get to the end and realize that the entire song is about the triumph of surviving the bad times and glorying in the good times.
The Band Perry's "If I Die Young". a sweet, upbeat tune about a young girl's death (or, depending on your interpretation, planning her suicide).