SlickWraps has a US$20 skateboard-inspired adhesive wrap for the iPhone 4 that's complete with scratchy skateboard grip tape on the back and faux wood grain on the front and sides. All of the necessary cutouts are there, including one for the Apple logo in the back.
Instead of it being scratched, the iPhone 4 will be doing the scratching. I imagine a phone with grip tape won't be all that easy to remove from a tight pocket, so think about that before slapping this on your device.
[via iPhone Savior]