Well, it isn't an official ATI setup but Sapphire has made a dual GPU x1950 pro. Yup, so that should be absolutely ridiculous. heres the link. DailyTech - Sapphire Debuts Dual-Radeon X1950 Pro
well i read somewhere that a quad SLI setup keeps up with a 8800 gt setup, on current game that is, DX 9. That said, i've also seen that the two X1950's are really close to a quad SLI setup, and in a few instances beat them. So, i think that a quad X1950 setup would absolutely rock the crap out of all thats out rate now, well i also guess how well that Sapphire would do with the drivers as well.
But an X1950Pro is equivilant to an 7900GS.... And quad sli of what nvidia cards beat the 8800GTX?, if its 4 7900GTX, its gonna cost more than getting a 8800GTX, and really, i bet all 4 of those 7900GTX cards would use more power than 1 8800GTX, or was it 2 7950GX2's? i still think it would use more power than an 8800GTX.