Well there you go, long time suspicion finally confirmed! Thanks Benson!
I had imagined that the pads were just second points for the original USB connector, as Benson mentioned, since it really doesn't make sense based on the location and device to be brought out otherwise.
Of course how practical all this turns out to be is another question, but with the ingenuity that's kicking around these forums I'm sure there will be some interesting (if only one off and impossible to reproduce) results...