Well, that will teach me to muse out loud!  I seem to have started something.

In my introduction I mentioned that I had considered applying MIDI
technology to the electric (not to be confused with electronic, by the way)
Concertola system at hand.  The significance to me of this musing is that
sometimes it would be nicer to have the Duo-Art playing  from a disc instead
of the changer.  This could allow longer programs, and would not suffer from
the occasional jamming of the mechanism as happens when the bars attached to
the roll leader (a single-point attachment) sometimes do not seat evenly
after rewind.

The piano has an electro-pneumatic interface, so MIDI would seem a
convenient way to go.

I agree with Mr. Rhodes that the Concertola itself would not be an ideal
roll reader, although it could be satisfactory if properly serviced
beforehand.  The contacts are simply spring wires (tungsten ??) that are
pushed against a common silver busbar by an inflating pouch which, in a more
typical player pneumatic circuit, is in exactly the same place you would
find the pouch of the primary valve.

The bleeds vent directly into the vacuum chamber that contains the contacts,
so fine roll dandruff can sometimes cause problems with them.

Although the Concertola has never destroyed any of my old rolls, I
instinctively do not really trust it with anything but recuts:

        The takeup spool turns backwards, so that when a word roll is
playing,  after passing normally over the tracker bar, the words roll up
against the spool instead of facing the audience.

        I do not know what the fastest rewind speed is for reproducing
pianos, but I think that if the Concertola isn't the fastest, it must be
very close to it.  Makes quite a buzz!

These are probably not desirable features for rolls with a tendency to shatter.

Hope this gets my musings back into perspective.