I have found the solution (from the ut2k3 linux mail list... thx guys) for my problem, but i don't think it will help you, jeff.
Basically for my problem you have to define a meta mode for a SINGLE display in the resolution the game wants to switch to full screen.
For example, i have ut2k3 set to run 800x600, and my normal 2 monitor desktop is 1280x1024 my metamode could be something like:
which at least get's ut on 1 monitor, full screen. (btw, it also works correctly if i have a 800x600,800x600 in my metamode as well. When apps request full screen the driver or x or someone must default to switching to a single monitor mode in the matching resolution. That might also explain why jeff can't get his setup the way he wants it either with twinview.)