I suppose if you leave the clear screen protector on the back when you first unbox it, and the bumper case with back exposed might be a viable option as well as a clear case, but since it is glass, you definitely need some kind of rubber protection, best viable option would be replaceable backs, since it does have two allen/hex screws on bottom and replace with other possible colors or even plastic or metal, chances are you will see them if breakage and scratching becomes a problem and if the back is simple to take off.
I have seen Phil unbox one Nexus 4 and it had screen protectors already installed front, back and the chrome too, I am hoping the front screen protector does not have the white arrows on it in the consumer release, I would like to always see a phone issued with already installed screen protectors without consumer having to go get one to put on it.