Though that article is a little confusing since the GTX 280, not 260, has 240 Stream Processors. But assuming that's a typo, 2x GTX 260s will be awesome, especially if it's the 216 SPU unit. For single card performance (which is for accurately single-slot performance), it should beat the 4870x2.
Drool... me want!!!
Haha, this is the best part of the article: "Oh, and first person to ask "will it run Crysis?" is banned. I'm not kidding."
I am waiting for the time when we can get around 65fps average with one single card and GPU in Crysis on 1680x1050. It's possible to do it at the moment, but it will cost you 3x 400 dollars, which is a lot. I can't wait to see how the GTX 295 will perform.