Twitch. Twitch. TWITCH.
I should not find this as beautiful as I do. Out of context, it's easy to understand - everyone has what they want. And then it comes into focus - Lin has her mother's name because Toph is a single mother.
But if you think about it, who says the Blind Bandit would have it any other way? She has power, she has freedom, she has respect, and she has no shame or guilt in her. She has an heir which she will raise in the manner she and she alone sees fit, the only immortality she desires. Why does she need a husband for any of those things?
Before she left home, she pleaded with her parents for understanding;
"I love fighting. I love being an earthbender, and I'm really, really good at it."
And now, she walks head held high, not pleading any more, but simply stating;
"My mind and body are of stone, and there is fire in my belly."
If you look with an open mind, I think this is where you'll find out where Lin Bei Fong came from.