Giz - Amazon *should* work if you can 1) recognize that it's an amazon.com link, and 2) just appened one of those endings to the link.
One or both of those endings could work, it'd have to be tested.
This wouldn't be like a formatting button because it'd have to recognize the URL pasted into a post by anyone - not someone purposely helping me to add my affiliate code to it.
That's why it's probably a bit harder than it seems...
