I think it might be possible to use two mice on the same computer, but you would have to write your own driver to communicate with each of them, instead getting their coordinates with GetCursorPos, having their events catched and distributed by the OS automatically etc.
Wii Remote is a good solution for your problem, so if you want a cleaner solution, you might have to wait for a while.
Thanks for your reply.
Do you know if they're close to getting the motion plus to work, or is it not looking likely?
Do you know how such a driver might be written for the mice? I've managed to get two cursors using teamplayer but my fps game still only recognises one mouse. I've tried CPNmouse but found it very laggy and it didn't get me any closer to the result of 2 mice in a fps anyway.
Is there a way of getting a gyration mouse input to be read by glovepie instead of by windows as a mouse? That could probably do it.