2x 6870 vs 1x 6970?

So my graphics card died and I had to get a new one a little while back but at the time the 6970s and 6950s were not out so I picked up a 6870. I am finding I want a little more umph for running stuff at 2560x1600 so I was wondering how performance would be with 2x 6870s compared to 1x 6970? The 2x 6870s does have the advantage for me of being cheaper as I already have 1.

Also would my power supply support 2x 6870s?

Current system specs:
AMD 9850 @ 3.0ghz
6 gigs ram
Corsair 1000w Power Supply
Areca 1880ix-12 raid card
DVD drive
Blu ray Drive
6x hard drives

Your PSU will EASILY handle two of any card.

2 6870's beat a 6970, however I would still want a single card solution.

Aside from the reduced case real estate and increase memory size (which to be fair would be a boon at my resolution) what reason would there be to run a single 6970? To me it seems like paying an extra $100 for less performance would be a poor choice.

buy a 6970 and once you're up and running with it, sell the 6870?