DrumKid is designed using KiCad. You can edit the KiCad files to produce a custom DrumKid PCB, or just use the Gerber files provided to order a DrumKid PCB from a manufacturer. The latest working, tested PCB is V6. V7 is coming soon with (very) minor revisions, and V8 might involve some surface-mount components because I've just learnt how to design/order pre-assembled boards.