The folks looking for this reference may be thinking of the "OrganEze"
project, which is fully documented at
www.organeze.freeserve.co.uk/index.html

There are plans in one large document for building a 49-note chromatic
organ, including making both flue and reed pipes using some
unconventional shortcuts.  It's not exactly MIDI -- the author has his
own circuitry based on ROM chips -- but it could easily be adapted to
MIDI control since he uses direct-electric valves.

Hope this helps the hobby.

Mike Knudsen