Thanks to Kramnik, oneTesla now does polyphony!
The relevant Eagle driver files are [here].
I've also rerouted the driver for sending out; the files are [here] in case anyone is interested, but its not really practical to send it out in low quantities.
My friend Daniel Kramnik built a variant of this coil with an optocoupled interrupter that plays MIDI (as well as a re-routed controller) and it works great - on the high notes it does about 12" ground strikes at 140VA.
The optocoupling really helps - it stops the pulsewidth from jumping around, allowing for more reliable operation and better performance. The coil now uses FGH60N60SMD transistors, which cost a bit more than the old FGH40N60SMDF's I was using and are a bit slower, but seem to be just beefy enough for reliable 250A operation (which is what the peak current roughly is in the above video).