The Analog Synthesizer SX-150 Mark II for sale at Think Geek features ten controllable parameters, line in and out, and a four octave range. You use an electrode stylus to play tones, but a printable keyboard overlay is available to play exact notes.
Analog Synthesizer SX-150 Mark II features
Pricing and Availability:
Two new modules from AJH with a lot of history behind them
I guess I've been trying to recreate a Korg Electribe all this time..
A new interface, bluetooth speakers and a neat looking portable mic/recorder