I was fascinated by the discussion and the examples given.
I found this video on YouTube of the Dortmunder Drehorgel group
playing in Speyer in 2011 and I hope that my computer skills are
sufficient to make it available to other interested MMDers.  The
location is  https://www.youtube.com/watch?v=6HzVi-TWekw
 

Jon Polden

 [ At about 50 seconds into the video the leader stops turning his
 [ organ crank and the music continues.  Amazing!  ;->  -- Robbie