Very neat project! I did something similar to an old Heyligers organ from the 70's. It was an absolute monster, 2.45 m tall, 1.5 meter wide, double manual and full pedal. I have it working with 'GrandOrgue', an open source organ simulator and it sounds and plays fantastic. Organs are a bit easier than pianos though because the outputs are binary rather than touch sensitive.

This:

http://forum.pianoworld.com/ubbthreads.php/ubb/printthread/B...

Two year project is the same thing but then for a grand piano action -> MIDI. It is super impressive but gives me the unspecified feeling that it should be possible to do this in a simpler way.