I'm sure others will also mention Bob Hunt's Virtual Roll system which
can be most simply described as "an electronic replacement of paper
rolls".  While optimized for player pianos (normal and reproducing),
it is adaptable for most any perforated media machine utilizing piloted
valving with tubing and tracker hole size roughly comparable to player
pianos.  It does not record live playing of the keyboard, but most users
do not buy it for that purpose anyway.  It is a robust, easy-to-install
system, and Bob offers great technical support; I know from experience.

John Grant

 [ See description at http://www.virtualroll.com/ 
 [ -- Robbie