ZenS, like you, I don't tolerate straight Gatorade well, though not to the extent that I regurgitate it. I can't speak to some of the other recommendations in this thread, but I've had good results with Vitalyte (except the orange flavor). The citrus flavor is probably the easiest on the stomach. They sell little 4 serving trial packets if you want to try without a big commitment: http://www.vitalytestore.com/

It might be worth experimenting with some different products to see what your stomach likes.