My son Sean really needs a case like this. He's on his fourth new iPhone since February 1. He goes through them like crap through a goose. Each iPhone ends up getting smashed. Gorilla glass cannot stand up to the rigors of life of my 17-year old. If it were not for the iPhone AppleCare program, he would be phoneless.
Vans, maker of iPhone cases, understands my son. In order to maximize the grip that one can exercise when holding an iPhone, Vans has created a waffle case, just like you would find on the bottom of a sneaker. Made of gum rubber, the case is available in white, black or pink. The case sells for $28 and you can check them out here: