And Phaelia's got it down -- from setting up button mods (she's using Bartender, one of Adam's essential addons for 3.0.3) to configuring the keyboard itself and even putting in macros for all three Druid forms, if you've ever wanted to use the Nostromo, there's probably something interesting to learn here. Seems really complicated to me -- I'm not sure if I'm willing to commit that much work into getting my interface exactly right, especially if there's a chance that a big patch could wipe it all out.
But I can see how half the fun of playing the game is getting the controls just perfect, and if tweaking things that much makes you play that much better, more power to you. If you want to dive into the world of custom controllers, Phaelia's guide will probably be invaluable.