Only Crossfire board I can stumble on is the DFI UT RDX200.
Then take a look at the number of SLI boards out there.
$199 for the board.
That X850XT PE is a connect3D . . . anybody ever run one of those?
You could get a X850 CF for $309 and a X850XT for $299.
A pair of 7800GTs would run you about $70 more . . . but you could get an Asus A8N Premium for $33 less . . . costing you $37ish more than the ATI build.
Do you play more Doom (nVidia) games or more Half-Life (ATI) games?
They need an artificial benchmark that simply averages a card's performance in Doom and Half-Life.
Personally, I had really been hoping for more Crossfire mobos by now.
If you were an Intel 'n nVidia guy, I would say take a look at Gigabyte Quad Graphics SLI . . .
Is just an Evil picture. Two bad nVidia does not have SLI support for 4 GPUs.
Oh well, too much ramble.