Chuck Cooper: Chef Kate Reinders: Wendy Hunter Foster: Kyle Michael Stuhlbarg: Kenny Cheyenne Jackson: Terrence Adam Pascal: Philip Julia Murney: Mrs. Cartman (give her a nice solo) Denis O'Hare: Mr. Garrison
I've thought about this a lot too, and come to the conclusion that really it wouldn't work. The film is just too perfect, it shouldn't be spoilt by trying to stage it. Sure, it would be great to play around with - some of the suggestions here are excellent, esp. the Canadians as puppets! - but there are so many different interpretations, finding one would be impossible.. and yes, the voices are too hard, and if it was on stage it would no longer be 'South Park' - it would be living, different actors.
It's like talk of putting Avenue Q as a TV show - sometimes some things just don't translate, and shouldn't. I say leave it alone, but love to read ideas. Personally I'd go with the many different backdrops idea, but with lots of theatrical big set pieces too - sort of like what Crazy for You did.
There's a big, huge glitzy style show-stopper in 'I'm Super', with lots of OTT tap dancing.. fireworks, etc. 'Blame Canada' would be riotous too. But these are songs that are away from characters - the ones relying on Cartman, Kyle, etc, would be too difficult because are they children, adults? Teens? (I mean on stage). They have funny legs too, you couldn't do it differently on stage unless it was a cheap off-Bway production and they kneeled.