For those of you who been living under a rock, AMD released the Radeon HD 4870 a few weeks ago which for ~$300 had as good performance as a $649 GTX 280. Today they released the X2 version of that card which we those of us without CF boards can buy (and its cheaper too).
Those of us with CF boards can buy two of these for quad crossfire (a few reviews did this and the performance gain wasn't very good.. but it might be different for 3x1680x1050).
(Some reviews)
http://www.techpowerup.com/reviews/Sapphire/HD_4870_X2/1.html
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/9225-palit-radeon-hd-4870-x2-2gb-video-card-review.html
http://www.tweaktown.com/reviews/1541/sapphire_radeon_hd_4870_x2_in_crossfirex/index.html
http://www.pcper.com/article.php?aid=605&type=expert
http://www.driverheaven.net/reviews.php?reviewid=607
I am buying one of these asap (can't find any stores that are selling it yet). As you can see my current specs are 2x8800GTS 640MB, and from my research this X2 should be about 50-100% better than my current two cards (I have a Th2Go so I game at 3840x1024).
Anyone who has bought GTX 280 SLI recently, you guys should really bust out the RMAs and return them :).
Whoever buys the first 4870 X2 CrossfireX (quad cf), please post some benchmarks are 3x1680x1050.