How about Michelle Rodriguez?
She has a good voice and can act like a badass, but her body doesn't quite match it either.
I really don't see what an actor's real appearance has to do with them providing a voiceover. Why do you think that's important?
(I'm not touching the rest of your post, which I think makes an unnecessarily controversial and broad statements about what roles specifically muscular women are suited for. But I'd suggest that when commenting on things that are likely to be personal and sensitive to some people, you aim for tact and try not to go further than you need to with the generalisations.)