I think that going with a trackball is the way to go otherwise your mouse arm might be over extended a bit. But as for some options away from the norm, I think a track-pad/joystick could also work out really nicely.
There are a few trackballs that a lot of people seem to like, the two on the top of my head are; the Kensington expert mouse and the Kensington slimblade. Those I just listed are also ambidextrous trackballs so you could alternate hands with the trackball pretty easily.
A trackpad with a ergo dox has been done before by rambunctious. I'm not sure how well it worked but here's a picture:
- XFC6KY4-crop.jpg (978.48 KiB) Viewed 4244 times
So as far as trackpads go I think the best is the magic trackpad that you see in the picture. You have to do a bit of leg work to get it to work with windows though, here's a link to a guide for getting it to work with windows:
http://www.labnol.org/software/apple-ma ... ows/14158/
A joystick would definitely be unique. I don't think anyone has ever gone with an all-out flight-sim type joystick with an ergo dox before. As for which joysticks are good I really don't know.
