RF Laserworks latest creation is a heat sensitive backing for the iPhone 4. Coming in at .005″ thick, the backing fits nicely under any bumper and changes colors in the range of 90 to 95 degrees.  Its priced at $12 USD, comes with or without the Apple logo cut-out of it. I emailed them to see if you can reposition it once its on, but still haven’t gotten a reply.  I’ll keep you guys updated. Get yours now here.