Personally, I don't understand why manufacturers would create external cases that snap onto the 521's outer shell, instead of simply replacing this entire battery cover. It's an extremely simple part made with basic mechanics, no antennas or metal connectors, just a set of push-buttons mounted to the side. It's almost like Nokia was designing the phone with the intention of 3rd-party replacement covers, perhaps integrated directly into a more complete (and more efficient) case.
Yet, with all the accessories China has pumped out so far for the 521, none of them directly replace this simple slab of plastic that makes up the phone's exterior color? Internet, I am disappoint.
(I want one in a dark blue. Or my own graphic. Something. I just don't want a bulky case... I just want to replace this plain white shell!)