Blaine Warner said, "I am looking for tune MIDI files that are
compatible with the John Smith organ, for use in punching rolls."
Have you looked at my web site?  I think I have posted more
20-note files for free download than anyone else.  Start at
http://www.wallace-venable.name/mechanical-music/index.html 

I have found that Alan Pell _sells_ 20-note MIDI files which will
work.  I consider the arrangements by Hiddo Van Os to be very good.
See "Music" at http://www.alanpell.com/ 

Alan asks a price of £12.95 for a MIDI file.  He will punch them
on "Raffin" 20er rolls for less, but he does not punch the Busker
140 mm rolls.

I think MMD regular Harald Mueller also sells MIDI files, see
http://www.haraldmmueller.de/ 

Wallace Venable