I've wanted to assign an application switcher button to my Contour ShuttlePro for some time, and hoped that the functionality might be included someday in a new driver, the way it is for Logitech mice. Well, I finally got tired of waiting and decided to try to fix it myself.
I found that the only thing preventing me from assigning command-tab in Contour's setup utility was the system-wide application switcher itself. So using information from hints (here and here), I came up with a step-by-step guide that should allow you to set these commands without having to restart your computer.
You could also follow this procedure to enter command-tab in any utility that depends on "sensing" your keystrokes to set its shortcuts.
$ cd /System/Library/CoreServices/
$ sudo mv Dock.app Dock.app.deactivatedsudo mv Dock.app.deactivated Dock.appMac OS X Hints
http://hints.macworld.com/article.php?story=20050517170125404