Back to front but not reversed...
Hmmm... i think this invention would work differently than you described in fact. You would want your finger on the reverse 'touch sensitive' side of the iPhone to move in the same, not the reverse direction (as you look at the front side display that is) as the displayed UI elements on the front of the device. This is a really very clever idea indeed... just try to imagine it on your existing pda or mobile and it so obviously would work really very well indeed!