I've tried Maya on a few different systems, one I tried with a single EVGA 480 was the best I've ever used, even with a high poly count, but our ideas on what makes a high count could vary wildly, since I only have a 250GTS at home, so I'm probably used to much lower than what's considered high these days

I guess you couldn't just return the 480s for a refund and find some 2xx cards elsewhere?

Also, on the 2-sided lighting thing, shouldn't you have that turned off anyways? I always have, makes it a lot easier to go between Maya and rendering apps/3DS.