Good luck with the mod.
Also, check out this string for details on the bezel change: blacked out with snake skin
Full props to poster michaelalanjones (also posted above) who did loads of typing to detail the step-by-step of the bezel change. I added some other tips in my last post in the string. I think the bezel change instructions take you most of the way. It is probably the tough part, anyway. Once it's opened up the keyboard is a separate piece, so it should be straightforward to swap it.
I didn't do a trackball swap, but I've heard that trackball assemblies from CNN may require you to flip the magnets to make it work properly. Do search in the forums for "trackball".
(if you go the Hardware & Accessories forum, you'll see loads of posts about mods) (in fact, I'm expecting a BBF moderator to move this string over there)
Pay attention to the various warnings about grounding yourself and discharging the capacitor. I'm no electronics technician, but there is some risk of frying your BB.
Good luck (and I'm looking forward to pix, too.)