A suitable motor to drive a Tangley or Coinola (Operators) music
roll frame in a calliope would be a DC motor for an electric scooter.
Such motors are available from surplus electronics firm and at 
Internet sites such as eBay.

Scooter motors manufactured for Currie Technologies have a wound
rotor with commutator and brushes and a permanent magnet stator, and
so will also work as a DC generator.  As a motor, the shaft speed is
proportional to the input voltage and the current varies with the load
torque.

A 1/6-horsepower (135 watts) 24 VDC 3000 RPM motor, including a pulley
for 3 mm pitch belting, is offered for $15 at

http://www.allelectronics.com/index.php?page=search&search_query=24vdc+motor 

Robbie Rhodes
Etiwanda, Calif.