This is a great thread. :) +1 for serial support in Chuck.
I've done a lot in the past with hardware interfaces and Chuck and have always run something like processing/oscP5 or a python/pyliblo script in the middle to send OSC to chuck.
Arduino (on a mac) uses the FTDI driver to expose a serial port. In a posix environment, can't we configure our machines to pipe the output of that file in the dev filesystem to a named pipe or something as a work-around?
mkfifo tochuck
cat /dev/usbserial-blah | tochuck
and then read from tochuck using file i/o objects? I know it's hackish, but what is nice is that you could configure your system to just do this all the time and then your students wouldn't have to constantly worry about booting processing and running some dinky little middleware app that sends serial over OSC.
You'd have to be careful to use an ascii based protocol on the arduino side. And, of course, you'd have to make sure to reset everything when chuck crashes with the file still open.
Just thinking out loud here...