So what else is there. Well actually there is those 1680x1050 screens. They would be ideal as they will have the small bezel, be larger than regular 17inch monitors and be cheap enough to buy three. But you may think 20 inch is to small. So the Dell 2007wfp is out. How about a 22incher. There are new 1680c1050 screens that are very cheap and 22 inch. A 1680x1050 screen won't have to scale all that much to display 1280x1024 and so would look great. In fact the Guru website used the Dell 2005fpw for their review of triplehead! Look in to it. It could be what you want.
TH2Go can power two (1680x1050) screens natively. So with 2 outputs from one graphic card (8800GTX/S) u could run three 1650x1050 screens at native resolution (when not gaming, one vga to TH2Go and one dvi to one of the 3 displays). When gaming you could route all three outputs vga from TH2Go to the 3 1680x1050 screens, each at 1280x1024/768 resolution. You will therefore be able to utilize all your screens real-estate when not gaming. And gaming at the maximum resolution TH2Go can support.
22 incher u mentioned are most probably all 6bit TN panels.