Trash80 suggested that we use the Circuit Bending forum as a R&D forum for the development of new hardware and software, so I'm posting my latest project here.
In addition to building ArduinoBoys, I plan on taking on another project. Problem is, I've got three potential projects and probably only enough time to take on one. Maybe you guys have a suggestion on which one I should take.
1. Further ArduinoBoy development. I think I could modify the software and hardware so that a single ArduinoBoy could service up to three GameBoys. By simply soldering two additional GameLink cables to the remaining 3 analog pins on the ArduinoBoy and with a few modifications to the software, I think I could create a few additional modes in which you have three mGB receivers or 1 LSDJ master with 2 LSDJ and/or Nanoloop slaves and start/stop/sync out.
2. Gorf sequencer: another open-source AVR-based music device developed by a fellow named Paul living in the UK. He's done some great work, but looking at his PCBs, I noticed they use parts that are a little tricky to find here in the States. Redo the boards with a few modifications for easier-to-obtain parts and a more readily available case (his uses a custom laser-cut polycarb enclosure) and a few more North Americans can see this puppy in action. Problem is I really don't feel like doing another "improve on someone else's idea" project. It feels too much like cheating.
3. It was suggested elsewhere on these forums that I do some interface work with a sound generator IC, and I think I found one: the Texas Instruments SN76489AN, the modern-day equivalent of the SN76489, most famously used in Sega game consoles and handhelds. It is still made (I'm pretty sure), so the parts are not running out anytime soon, and a brief look at the data sheet makes it look not that hard to use. I'm waiting for a quote from Mouser for 10 of them for experimentation (they don't have any in stock). It is the most ambitious and most likely to fail of the ideas, but it is also the project I'm most excited about.