This may be an even dumber question, but have you tried the Mighty Mouse? I'm counting 4 buttons on mine right now (left, right, center, sides... the squeeze). I've been using the Mighty Mouse since its debut and have no complaints whatsoever. It has the best Mac OS X support possible (don't think I had to say that) and is very familiar for those who've used the original one button Apple mouse (it has that low profile you speak of).