For sale, available from USA source: MIDI players that use a SD memory
card for file storage.  Simple unit is player only.  Other models will
record MIDI input, transpose, and have other functions.

New product: Modular Magnet Driver systems.  MIDI input converts to
magnet driver.  System can be built with modules to operate up to 128
outputs from a single MIDI input.  The magnet driver modules are built
in multiples of 32 driver circuits.  Up to four modules can be plugged
together to get the 128 outputs.

The controller module has a MIDI IN socket and MIDI Thru socket and the
modules can be chained easily with a short MIDI cable.  The outputs are
field programmable to accept any note(s) on any channel(s).  An example
is a 150 style band organ using one controller module and two magnet
driver modules programmed to play notes on two channels.  Individual
drive current is rated at 500 mA.

We have amplifiers available to deliver 1.5 ampere per driver that plug
into the driver module in place of the ULN2803a chips and a remote
mounted board that can switch up to 5 amperes per driver.  Some photos
and information are available at http://klingerorgan.com/ 

Bill Klinger
Flippin, Arkansas