Construction of the register board is complete and it seems to be working perfectly. It took about three weeks to design the PCB and after getting it made by Express PCB, it took two days to solder the parts on and get it working. That includes hooking it up to a microcontroller which I've programmed to run a simple 'torture test' to drive the board and detect errors. This was almost too easy and has convinced me that PCBs are the way to go from now on if I want to get LEO-1 working any time soon.
The operation of this board is explained here.
A video showing the board in action is here.