For reference, a theremin cello is similar to the classic thermin of 50s sci-fi sound effects fame, but packaged with a neck and played like a cello with the left hand selecting pitch along the neck, and the right hand controlling attack and volume.
Whereas a guitar has several (usually 6) stretched strings and selects pitch with a similar UI with the left hand, and controlling attack and amplitude with the right hand, but in a very different manner.
But is there a neck design which incorporates both systems? And some crazy electronics to switch and blend? If not, can I patent it?