> ... the Gerety-Chase valve blocks would be suitable, if they
> can be purchased separate from their electronics.

I think this would be your best bet but I don't think it would be very
smart to remove the electronics from it.  The magnets are controlled by
a "pick and hold" system that puts extra power to the magnets to get
them to open, and then reduces the power so they will stay open and not
overheat.  They would probably burn out if you just applied full
voltage to them.

As far as the problems with the valves being built to be chromatic
and the music being played not nearly-diatonic, you could have a small
electronic MIDI translator ("black box") placed between the player and
the valves to transpose (translate) the notes as needed.  In fact, you
could translate the MIDI files on a computer before loading them into
the organilleros' player system.

Here is a link to a page that Terry Smythe sent out just yesterday.
This man made his own valves: http://members.shaw.ca/smythe/coggins.htm 

Pete Knobloch
Tempe, Arizona