Damon et al,  The electronic kits cannot be purchased new unless you
are a piano dealer.  However, there seem to be more used PianoDisc PDS
128s for sale, most of them being removed for upgrades.  I installed
a used PDS 128 system in my Knight console piano last week.  I was very
impressed with this system -- it has good repetition with power to spare.

However, putting it in a piano requires a lot of measuring and planning
before you dive in, and it's not a job for the novice.  Anytime you cut
a slot in a upright keybed you are certainly going to throw off the
regulation, and if done incorrectly in the wrong place, it will forever
affect the touch of that piano.  Also, beware of the plate keybed
supports being in the way of the rails.  Some people simply saw them
off; please do not do that as it affects the integrity of the keybed
and key regulation.

What I would suggest is to find a good quality tall upright and install
the system above the keys just like a pneumatic stack.  I did this to a
Pianomation system with great results.  The piano doesn't have to be
modified and will play just as well, and it is also easier to service.
My favorite piano to do this to is the old upright players made by
Baldwin.  These pianos have a commanding tone if in good shape, are
easy to find and have a built-in stop rail on the piano action.

I do have a complete PDS 1000 system that I have not installed yet;
if you are interested in it contact me directly.  Music is easy to find
thanks to the people who scan rolls.  Simply do a Google search for
"player piano MIDI" or "player roll scans."  QRS also sells MIDI files
of their rolls.

Good luck,
Andy Taylor