As an aside, the fastest film I ever shot was T-Max 3200 (discontinued!), which I'd then push a stop further using proper Kodak T-Max developer. For my purposes at the time (high school yearbook photographer), we never, ever printed larger than 8x10 (typically 5x7), so it just didn't matter at all. I actually made some 11x14's for myself, and so long as you're not sticking your nose into the picture, they look fine.

Today, any of the cameras we're talking about give you radically better speed and noise and resolution than any film emulsion could ever do, particularly at high speeds like we're talking about.

Back to the topic at hand, since you're stuck with the lighting you've got, you need to look at all the other techniques you can bring to bear on the problem. You can rent/buy brighter lenses ($$$ + heavy weight + tight depth of field). You can use a tripod or monopod to allow for a longer exposure (but longer exposures only work when the actors aren't moving much). You can also get fancy in post-processing; Lightroom is pretty good, but supposedly you can do better with things like Noise Ninja (which has now evolved into a full-blown raw conversion program: Photo Ninja, which seems to get strong reviews). Also, I'll note that when you convert to black & white, you can get away with more because it just looks cool. A little bit here and a little bit there can add up to a big difference in the quality of your result.