I just finished modifying this Four Voice for a customer.  The synth had the NEA Pyxis aftertouch system added as well as a modular expander cabinet.  The cabinet brings all of the functions of the synth out to the front panel and contains an array of mixers, electronic switches, portamento, etc.  We modified the S&H circuits to allow users to sample any waveform, not just noise.  We have an in depth demo of the synth recorded, but are still in the middle of editing the video.  Here is a short clip of me trying out the aftertouch.