ATI can do Eyefinity on Crossfired cards, since 9.12, also the reason it takes 2 Nvidia cards in SLI is because it
doesn't have Displayport. Displayport uses no clock generator and all these modern video cards only have 2 clock gens on them, so only 2 video outputs per card. So you either need to add in the 2nd card to get another clock gen, put a 3rd RAMDAC onboard, or use Displayport since it doesn't need the clock signal.
My only contention with Surround 3d is that most the 3d on the peripheral views is a waste because you need both eyes over there to get the 3d effect. But it still sounds cool, I can barely afford a 3 monitor Eyefinity setup though, no way I can afford 2 graphics cards, 3 120hz screens, and a pair of glasses

Maybe in a year after the dust settles.. Bit Cauldron's glasses look a lot better than the current crop anyway.