It came across my mind when I was thinking about how to do my pedestal cab. I am going with a different option, but I will tell you what I was going to do.
If you have a kitchen sink with one of those spray hoses, then is basically the same concept. In the inside of the cab, just have a pulley and a counter weight. Nothing too heavy that you would be fighting against. The idea is to have enough weight so that you can guide the usb cable back into the cab with little effort. It wouldn't snap back automatically, but would make it easy to retract yourself.
You can probably find a real retracting cable that locks and snaps back. I am cheap though. I have a 2' cable that does that, but it is very thin and flimsy.