For those discussing ribbon controllers DIY, I found these excerpts on the
web; hope this helps:
"There is information on building a ribbon controller in "Electronic Music
Circuits" by B. Klein. This one is basically a rheostat using a long strip
of conductive foam such as you find protecting semiconductors from static
charges. The foam is placed on non-conductive material (wood, etc.) and two
metal plates are attached at each end. One plate is connected to ground and
the other to a +15V supply. Now, at a slight distance above the foam you
place a piece of metallized mylar film that leads to the Control Voltage out
jack. When you press on the mylar film it makes contact with the foam
somewhere between 0 and 15V. As you slide your finger along the film, the
voltage changes."
"I added a 2-foot long ribbon controller just above the keyboard, with a
range of about +/- 5 octaves. I used black rubberized anti-static bag
material for the resistive element, and a steel band about 1/4" wide for the
ribbon. I mounted a separate linear power supply inside the case so as not
to disturb the existing circuitry. The ribbon is buffered by a TL-082 which
simply goes straight to all 16 VCO's via a 100K 1% resistor added to each
VCO's summing node. There is no memory S/H cap, so the pitch is only
affected when you press on the ribbon. Autotune still works, as long as you
leave the ribbon alone during the tuning process. Now I can do CS-80 bends
and get the VCO's down to a couple of hertz."
"There are several [vendors for the resistive vinyl element], but one that I
know from the top of my head is
http://www.interlinkelec.com/ I don't know
their current line up, but they are company we used back in the Oberheim
days.--Tony Karavidas, Encore Electronics"