This is what my breadboard now looks like. It is full and it does what I want it to do for now. Time for a bit of a code cleanup and then I can show what I have achieved so far.
Even though I use a big 40 pin PIC for my experiments I decided to try how sharing output pins for multiple purposes works. To do that I use two 74HCT573 (PDF) octal latches. The goal is to drive 16 outputs from 10 pins. If you add one more octal latch, it only costs one more pin to drive 8 more outputs. So, with 16 pins and 8 octal latches, you could come to 64 outputs.
I also added an output stage with a reed relay. My final goal is to make a variation on the looper project that can be found at jimkim.de.