Best I've come up with is to tie wrap them to the wall. There's no way to make them look nice on a backboard. If rack mounting the system on a shelf, it's not as big of a deal.
I hate power bricks anyways. Wish they were either smaller like Marvo said, or have a little bit bigger box with an internal power supply. If they were "stackable" like some of Cisco's power bricks, that would help (where one power brick snaps onto the back of another).