Did you forget about adjustable pitch propellers?
We have managed to use human-scale ones even to synthesize low-frequency audio by building a sealed room and putting a reverse-thrust-capable one on the only opening of that room (besides a closed door). It spins and the pitch is adjusted to modulate thrust in response to the sound signal.
Those rotary woofers deliver supposedly good distortion up to their rotation frequency; 13 Hz / 800rpm seems common.
For reference, a tail sitter propeller would probably spin faster than that, though even this is plenty to control the aircraft. A blade design using a servo flap easily keeps up with those control speeds, and could likely even offer thrust vectoring like the rotor of a helicopter (could eliminate the flaperons).
