Though technically not fanon due to being created by a company to be the Mac response to Vocaloid, Macne Nana is the very first voicebank that can be used in UTAU to get an official Vocaloid voicebank.
Oliver's bird has no official name, but a number of fans decided to call him James, and the name stuck — to the extent that even the VocaTone staff have begun using it, but they stated that the name is still not canon.
Cash Cow Franchise: A huge hit in Japan and overseas, to the extent that there are musicals and even concerts of them!
Gakupo was based of voice samples from Gackt. Then Nico Nico held a vocaloid contest hosted by Gackt where they asked him to sing the winning songs Episode.0 and Paranoid doll. The result was Gackt not only created and released a remix of the song Episode.0, but also created a video that was identical to the original pv but with the pictures of Gakupo replaced with pictures of Gackt dressed as Gakupo. Here is the original pv of Episode 0. And here's the Gackt version featuring Gackt dressed as Gakupo Episode 0 Gackt version.
Vocaloids themselves for Sharon Apple. Synthetic pop-star, human vocal element, live holographic concerts...
Development Hell: The Hibiki Lui/Ring Suzune duo is currently stuck in this with no release date so far.
Gumi is nicknamed "Rankaloid", due to the fact that her provider Nakajima is more well-known for the Macross Frontier character, Ranka Lee.
Quite a few fans have started using the nickname "Lenny" for Len, due to the number of PVs in which he dies. In the Japanese fandom, he tends to be called Ikelen (Cool Len) whenever he's portrayed as cool or badass, which is based off the Japanese term "ikemen" (roughly, cool guy) and variations of it seem to be common within Vocaloid songs featuring a character being badass; Ikerin shows up less frequently. Additionally, whenever his The Casanova side comes to the fore, he's tagged as Maselen (Mature Len).
Among Brazilian fans, Maika is also called Maikăo ("Big Maika").
YOHIOloid's are Hio or Yohi. VocaTone members have gotten around to calling him Hio, even in some of their official talks.
Many of the non-English Vocaloids are rather difficult to get if you don't live in Japan, and shipping can get to ridiculous prices. Yamaha attempted to avert this with some Vocaloid3 banks such as VY1V3, Mew, Aoki Lapis, Tone Rion, and the V3 Gumi banks available as downloads; Voctro-Labs ships Bruno and Clara internationally; and SBS put up SeeU on eBay, albeit at a considerably higher price; but some, like Yuzuki Yukari, are still rather difficult to get overseas.
Do you want to buy an album by your favorite composer, or a compilation album? Unless it's registered on KarenT, you will probably never be able to get it, because they're usually sold at Comiket or VocaMas - and even if they're sold online too, they're usually on Japanese-only sites.
Even if you can read Japanese or use a translator, good luck seeing any of the Theatrical Plays based on the more famous songs. Those few that do have DVD releases never seem to have subtitles, English or otherwise.
And then there's the licensed games, notably the Hatsune Miku Project Diva series, which were Japan-only until Project Diva F, which at least was made available in the Southeast Asia region, but that's still in Japanese. There are hopes however for the latter to see international release, seeing as how an American promotional video for the PS Vita shown in Gamestops shows gameplay footage of that game.
Averted with Project Diva F for the PlayStation 3, in which the localized version of the game in the US and Europe,eventually released on August 27, 2013 after an announcement by Sega.
Sega then topped the release of Project Diva F, when they released Project Diva F 2nd. Several fan favorite songs? Check. Playstation 3 and Vita at the same time? Check. Full English Subtitles, even in the Diva Room mode?! CHECK. Cross-save, even from the original Japanese release? ... SEGA out-did themselves.
We haven't heard much of CV04 and its existence since its confirmation in 2009, and details get more and more scant as time passes by. Word of God says that he's still in production. However, he might not be in the Character Vocal series anymore since he's now listed as "Male Vocal" rather than "CV04".
Suzune Ring and Hibiki Lui seem to be pretty much abandoned.