[pewpewlasergun]

Couldn't you get the same benefit by just using the Arduino bootloader and including a USB connection? That way things could be reprogrammed in the arduino environment and you could still use your custom PCB. If nothing else it would be much cheaper, and you wouldn't be constrained by the arduino's size/layout.

[ricberw]

Agreed, it would be cheaper, and there wouldn't be size/layout constraints - but I'd rather let people continue to hack with the products, and for that reason, it seems to make more sense to me to keep the Arduino in the picture.