Yes the hole could easily be done I have seen examples of it. It would just need supports. We should be able to build a pc board to do exactly what we want think along these line a flat pc board with circuitry on top edge four pins come out bend 90 below the board. if we use pins we could simply plug the correct usb on(either male or female) then on the opposite side( the bottom) you have three connectors coming directly out of the board, one as an possible input and two as outputs( one for use as an output to the other wall if needed and the other going to power the cube function). That way we could use the same board for both sides since we could swap out what attaches to the pins on the top edge. It would all be serial I believe so the actual paths should be fairly simple.