My main concern is the 680 sli compared to its 700series eqv. Revolution or Evolution, if the 680 sli is only like 10-20ish fps lower or 20-30% lower in performance then we might as well stick with it.
So you want to run Nvidia surround? on 3 monitors? That's going to need some serious horsepower and budget. At the end of it all what do you want to pay? Because right now i'm thinking 3 680s, as 3D, triple mons are extremely demanding.