I'm going to start a "Project Development" thread soon to give some insight to what's being worked on.
The best way to donate would just be to buy a PCB that you want. Otherwise it'd probably just be messy...
If 10 different people donate $10 and each person wants something different we haven't really made any progress towards a goal, and 9 people are going to end up disappointed. I'm not sure how to keep it organized, but I'd be open to ideas.
Of course if anyone wants to loan a pedal for inspection (and be compensated for the favor with PCBs), that is always an option as well.