You can always get 2x 6950. Faster then the 560ti, more vram for bf3, better performance then a 580.
They prob are a bit more expensive then 2x 560ti, but better.
Alright. Thanks for the help you guys. I went ahead and got myself a 580, and if it turns out I need more down the line, I can get another and SLI em like you guys suggested.
Thanks for the help I can't wait till it comes and I try out BF3 on it