Do these exist? Obviously, they will all scratch to a certain extent. But, do they make one that is made out of more of a, robust glass-like material? I've got this one at the moment, which is an Gear4 Icebox: It's only been on a few days and it's already completely scratched on the back. I love the case for protection to the iPhone, it does the job really well, it's just the clear back looks really grimy now. Can anyone recommend something?