Why stop at performing innovative music with a theremin when you can innovate on the instrument as well?
The Syntheremin is a hybrid synthesizer/theremin instrument conceived of by Japanese musician AQi Fzono. The instrument "has a series of antennas and each one corresponds to a parameter, so the parameters (pitch and volume like regular Theremin, plus filter, Q, envelope, LFO speed etc.) can be controlled real-time just like an analog synthesizer with a lot of knobs." You can hear the Syntheremin on on AQi Fzono's 1998 album "Cosmology".
Special thanks to Jessica on SPELLBOUND-L for finding this!