They wouldn't need to be *that* big. For live action it doesn't need to be that extreme and they don't necessarily need to match Bengis design art exactly (besides you can't) but I don't think it's unreasonable to try and find someone with a very athletic look to her legs and the rest of her.
But I also don't think it's totally unreasonable to be able to make a movie that looks and feels like something that has jack all to do with the game. ****, I don't even play the games (though I have played them before) and I can see that you could get something cool out of them without just making a generic action flick with only slight visual reference to the game itself.
Also, I'll never understand why the hell Ryu doesn't get to be the protag in these movie projects. Chun-Li is a better choice than Guile but still it just seems off. I know people complain about his power levels but I'm just talking in terms of character. Ryu is afterall your sort of arcetype martial arts hero cranked up to 11 and to some extent he's the face of Street Fighter. The guy who is always prominently featured on the box and promo stuff so why not give him center stage and then let us see the SF world through him? He's our starting point and then we get an ensemble of heroes and villains from there.