I have converted 2 electronic organ consoles to MIDI and put computers inside them to run Puppy Linux and either jOrgan or MyOrgan. I'm currently working on my third MIDI conversion, now using MIDIbox boards (http://www.ucapps.de/). It is a three manual Conn theatre organ console, so will take a while to finish. My first was a non-functional Hammond L100, my second was a Keinla (German analogue organ that has been off the market for more than 20 years). I'll post some more details and links later...
GrahamG