The PIC can also be integrated with my other components onto a single board, so it can occupy less payload space that way
Hmm... I'm definitely not a hw guy, but from what I've seen arount the 'net, self-made arduino boards shouldn't be that difficult to build.
Also, there are commercial arduino boards that are quite small. Nano and mini, here: http://arduino.cc/en/Main/Hardware
My 2 cents
