Sorry to have been "lurking" so long on a topic that's close to home
for me.  I play a large cart crank organ (Raffin 31/84) and have made
many arrangements for it, including my own compositions.  I used to
punch music rolls, but now it plays directly via a MIDI interface
I built into the organ, using a Palm Pilot PDA to store the tunes.

I agree with Ingmar Krause that each tune must be arranged specifically
for the organ in question.  Sometimes I think you're better off to start
from scratch (melody and chords), rather than to take an existing MIDI
file and whittle it down to fit the organ's scale.

I have stirred up a little controversy at COAA rallies by playing my
own "modern" piece, The Lonely (nee Homely) CoEd.  It's from the early
1960s but has a sort of rock beat.  Some fellow organ grinders think
it's great to have newer style tunes playing; others say we should
stick to the old barrel-style songs.

More recently I arranged "Tequila" (mid-50s) and the Beatles' "Back in
the USSR".  Both get lots of positive crowd attention when I play in
public.  Kids today still respect and like Beatles music.  There are
plenty of pop/rock tunes from the previous generation that are still
well-known today, even without a "Mamma Mia" to put them back in the
limelight.

Some pop and rock tunes just seem to say "put me on your organ."
I woke up one morning with Canned Heat's "Goin' Up the Country" in my
head -- with its flute solos, it should really sing on the organ.

Each tune should be judged on its own merits: Will it work well on the
organ, and will audiences like it?  There are some "classic" pieces,
like "Stars and Stripes Forever", that I won't try to arrange for
organ, simply because there are too many chromatic notes that my organ
is missing.  Other tunes may depend on masses of brass or other sounds
that my pipes just can't reproduce.

As for the expense of getting good new arrangements, well, I cheat,
and I make my own.  Some of you could make your own, and have someone
else punch your roll from your MIDI file.

Anyway, I don't prejudge a tune by its type -- my monkey can't tell the
difference!  :-)

Mike Knudsen