Just a further illumination on Ken Caswell's piano [001130 MMD,
Welte-Mignon Classics on New Pierian Audio CDs]: it is an early-to-mid
1920's Feurich upright which originally played Red Welte rolls.  As you
would expect, the action has been completely gone through, with new
hammers and felts everywhere.  Ken had it converted by Jim Miller to
play Licensee rolls sometime in the 1970's.

It has the cork-in-the-bottle expression valve mechanism, the stack
has primary and secondary valves.  Miller added individual bleed
control screws, but these are not used as they clog up too much.

The piano had a DC motor with the speed increase, but that, and the
four-cylinder rotary pump, were discarded in favor of two remote vacuum
boxes: one to run the stack and expression mechanism, the other to
handle the demands of the sustaining pedal (the boxes are located some
60 feet away from the piano, in the garage).  The roll drive is a
Bodine DC gearmotor.

This is probably more info than anyone ever wanted about a piano, and
whether you agree with the modifications or not, it certainly delivers
incredible results!  (I hope I haven't opened the 'authenticity' can of
worms again.)

John McClelland