Nice set-up, though I thought you would go with an evga sr-2 and quad sli gtx 580's. ;-p (though you need a really big case for that monster board!)
As for Tri sli/tri crossfire on a sandy board mobo, I'd think that something like the Asus Maximus IV extreme (or Z version) would be good enough for it? It has an extra NF200 chip on it to boost the available PCIe lanes.
I was wondering about your choice of dual channel RAM as well since X58 boards run best with triple channel, right?

starcraft: "I and every PS3 fanboy alive are waiting for Versus more than FFXIII.
Me since the games were revealed, the fanboys since E3." 


Skeeuk: "playstation 3 is the ultimate in gaming acceleration" 









