And I do know where to find emacs, Russ. But thanks for asking :-) (I too no longer know where to find the 3-button Logitech's. I stopped at London Drugs on the way home from work today. They've never let me down before, but today, alas ...)
It's a bit pricey, but I love this trackball. I don't like really using anything else. http://www.amazon.com/Kensington-Expert-Mouse-Optical-Trackball/dp/B00009KH63/sr=8-1/qid=1163607770/ref=pd_bbs_sr_1/104-0020716-2518348?ie=UTF8&s=electronics 4 buttons, a scroll ring and a wrist wrest, and I can chord copy and paste in Mac OS X with the software (for 2 pairs of buttons anyway) and configure it on a per-application basis. It's pretty neat.
--lyndon
