This is fantastic...
A question. What happens if you do try and play a chord? Does it do the typical "I don't know which note to pick" freakout?
If it does, I have a variation on this idea that could be pretty interesting. What if you were to have a tap tempo (and/or knob) driven way to pick when it samples the frequency. Let it pick one and hold the note until the next sample. Sample and Hold. Could make for a nice random accompaniment for chords.
I'll probably take off from your design and make a go at this. So great.