Thanks for the positive feedback. I'll probably go the route of offloading the screen/inputs to an arduino. It's just frustrating because I'm so close to being able to do everything with just the axo.
As far as my build goes, it's a 6 oscillator wavetable synth. Two of those are 8-note polyphonic (the top two light gray rows), and the other four are monophonic (the darker gray rows). Each oscillator can be toggled as either a wavetable or noise source. Each has its own filter and a 64-note arpeggiator, as well as amp, pitch, and filter envelopes. I also recently added a pretty basic additive harmonics feature to build up interesting waves.
I designed it so that each oscillator can be used as either an output voice or a mod source for any of the others (vibrato, tremolo, gate, filter freq, filter res, and arp rate). I used extended frequency ranges so each oscillator can be set anywhere from .1hz to 22khz (from LFO up to anywhere in the audible range). Most of the buttons are used to quickly toggle things on and off (envelopes, tracking, wave/noise, etc). I can also set different midi channels for each oscillator as well as different key ranges (to do split keyboard patches). My latest goal was to dual-purpose the main block of buttons to also function like a drum sequencer. I have it working but had to comment some other stuff to reduce the size of my compiled code (hence my original post).
To create wavetables I made a separate web app where I can open up an audio file, zoom in on a specific section, and copy the data out to load onto my sd card.
I haven't recorded a demo of it yet, but I definitely plan to. I was hoping to finish my next build first (this build was designed before I added the graphic LCD, and I'm also adding a few more buttons and possibly some built-in speakers).