I wound up at a Simon Shaheen (oud/violin) concert with his ensemble and singer. My knowledge of Arabic music is very limited but there were some very beautiful melodies in the slower pieces that I thought might be approachable for theremin. Not to try to do them exactly (the ornaments and the microtonal system would make it very hard to even think of doing authentically... I think...) but maybe adaptations of some sort.
Peter, I'm guessing you've been down this road. Any thoughts? Any repertoire suggestions from this rich world I know so little about?