Thanks for the great thread. I know that this is old, but I just wanted to report that using the xorg.conf originally posted in this thread, I was able to get 3 1440x900 monitors working perfectly on my dual eVGA 8800GTS cards (Ubuntu Hardy Heron 64-bit with latest drivers from the NVIDIA web site).
Then I just needed to move over my keyboard layout and mouse configurations and I'm a happy TH2G user again.
Thanks so much for your help! If I ever get two TH2Gs and the corresponding sets of monitors, I know where to go.