It always becomes a ppd/w affair... sure, you could look at what Capt. Vortex has (had?) for sale, his socket 771 dually:
http://www.hardwarecanucks.com/forum...ard-600-a.html
It would definitely output a whole lot more than your ATI GPUs, and power consumption should still be in check. Use Ubuntu as an OS, and it will run bidagv no problem.
Check it out.