If you haven't heard it yet, 15.ai had a ton of voices. IIRC it was a single person team, and they were working on an mechanism to build a decent voice model from minimal training.

They had trained on just about every character in "My Little Pony: Friendship is magic" and various characters from other games (Portal 2, etc), and it was remarkably good.

It's been down for months though, claiming that they're having a hard time training the latest iteration of the model :-/