Do you know if there are any affordable "theremin" like MIDI control devices that enable free assignment of parameters to the antennas? For example, I could have both antennas control pitch, independently of each other, and amplitude would be set to a fixed value via a knob or on a device that the "theremin" sends its output to.
The D-Lev has a fairly extensive MIDI implementation, and you can control any CC with the volume hand (7 or 14 bits), so perhaps something like this would be possible if the synth it's driving is flexible enough.
There are 50 or so kits spread out all over the world, some in the hands of the world's best Thereminists, which has been quite gratifying. But the project has been in a bit of a hiatus while I do more R&D, and the current tariff situation isn't exactly filling me with enthusiasm. Enclosures and antennas have been a burden for some, a wine box build is probably your best bet. I don't mind supplying hand-wound coils and any guidance you may need. My contact info is on the support page.