I saw that you are (were?) running 4 monitors with Ubuntu 8.10 and two Nvidia cards (http://stackoverflow.com/questions/27113/how-to-use-3-monitors). I was curious if you were doing this with Xinerama, a hacked up TwinView config, or multiple X screens, or some other method? Does it work with compiz?
I intend to run my Dell 30" in the middle with two 1280x1024 on the sides and continue to use one X screen, and run compiz, on Ubuntu 9.04. Currently, I am using 2 monitors with twinview and compiz, which runs fantastic. I just can't get the third monitor running (unless I enable it in its own X screen, and then enable Xinerama to enable windows to be dragged as if all one X screen, but this breaks compiz, and I don't care much for having separate X screen).
I am very interested in knowing how you set up 4 monitors with 2 GPU's.
Thanks!