Seek calliope conversion to play MIDI files.

Help!  In the late 1960's or early 1970's my father, Ron Nielsen,
manufactured for a very brief time (until he realized there was
not a strong market) a 53-note brass whistle calliope under the name
of "Cleartone".  From what I can tell it is similar to a National,
complete with a keyboard, which uses an off-instrument source of
air to power the whistles.  There were about a half a dozen of them
manufactured, with one still in his possession and he has since lost
track of the others.

Anyway, my father still uses the instrument in parades in his small
town of Yampa, Colorado.  The problem is that his five song rolls no
longer play long enough to accommodate the parade that has grown in
length and route.  In addition, the rolls are getting harder to find
and have a propensity to tear over time.

Is there a manufacturer of a MIDI conversion kit that I can contact
that would still use the air tracker bar that he has in place?  Because
this was a custom manufacture I am not sure what he uses other than
vacuum tubing to power the thing.  Any questions I would need to ask
him would also be helpful.

Regards!

John Nielsen

 [ At http://www.steamboattoday.com/news/2001/jul/21/letters/ 
 [ "Yampa is a small town in Routt County ... of fewer than 500
 [ people, yet we swell to about 1,500 for the Fourth of July. ...
 [ The parade included children, floats, horses, antique carriages,
 [ bikes and a band.  Ron Nielsen played his calliope."   -- Robbie