i use mac too. the software for the arduino boards - an atmega168 chip - is available for mac, linux and windows.

if this idea did go ahead, there could be arguements in favour of keeping it arduino compatible, since there is so much code already out there, and arduino is compatible with max/msp and pure data.

i am, however, totally biased, since i've done my stuff up till now on the arduino :)

stu