Just a quick update - the project is still alive, just went on a brief hiatus! The pedalboard concept has been completed using reed switches & works perfectly with Hauptwerk. I may upgrade the reed switches I used to a higher quality in the future, as the the junky eBay ones I bought in bulk aren't the most consistent.
In the meantime other parts of the console are in process. We managed to find 2 nice piston rails on eBay which will be used with the 3 M-Audio Keystation MIDI keyboards. I'm considering redesigning the MIDI shield and using a Teensy 3.2 to simplify the MIDI software, as I need several more inputs for the piston rails, stops & pedals.
More detailed updates shortly!