The 6950 can handle Eyefinity fine, however, if you aiming at Eyefinity and have such option I would reccomend getting the 2 gb model.
I'm myself running 3240x1920 three screen portrait with single 5770 atm and the fact that I have only 1 gb of vRAM feels more limiting than the lack of horsepower in the card. With just 1 gb I'm sort of "hitting the wall" at AA higher than 2x. As 6950 has twice the memory bandwidth it should be able to better ofc even with 1 Gb.
Yeah I think its already implied by the OP that he has a 2gb. Only 2gb models flash to 6970.