This is certainly very impressive, but I don't think I'd ever actually use it. Two things that I didn't really like:

1. Tons of generated code in -drawRect:

2. When the UIButton was created with the background image, it looked to me like the image was actually the size of the button. It's much more efficient and flexible to make a small stretchable button background.

That said, very cool! I wish there were a trial version I could at least try out.