Hunchback (for Magic Mouse)
Update: You can now purchase my most recent version of this design (after years and dozens more iterations) from Amazon: mello for Magic Mouse (this is an affiliate link and an advertisement).
Attachment for the Apple Magic Mouse*.
The magic mouse is the only one I've used on the mac that implements touch scrolling decently, but I found I couldn't use it for more than 10 or 15 minutes without wrist discomfort. If you have the same issue, you may want to give this a try.
*affiliate link