I received some super nice components from Mouser today. I usually order from DigiKey because their shipping is cheaper and super fast. But I couldn't find the Bourns encoders I wanted anywhere but Mouser. I picked up the charging, boost converter, and audio codec ICs there as well. Boards will arrive next week.
I've also been working on the firmware and refactoring the quick and dirty code that I've written into a proper, more extensible structure. I'm hoping to abstract the Teensy audio library slightly to make it more flexible. Unfortunately all waveform generators, filters, effects, mixers, and the connections between them must be declared at compile time. I can tweak parameters and mixers at runtime. Hopefully I can pull off some smoke and mirrors to make the user experience less rigid.