As this project refused to stop occupying my brain, more stuff just kept coming. Now there is a PCB and diy kit for building what I've called the T. Chordstrum. It uses either the tlc strummer firmware on a Teensy LC, or the Teensy 3.2 version of it all, with the addition of built in audio output. I even put a rhythm section in there, with samples from the Keio (Korg) Minipops 7. And it keeps on developing...