SparkFun has another (maybe even better?) board for AT90CAN128:
SparkFun Electronics - Header Board for AT90CAN128
They also sell the bare board very cheaply:
SparkFun Electronics - ATMega128/103 Bare PCB
Thanks for the information on the CAN bus. I'm not fully sure we'll ever get there either, but it would be nice to try.
CANについての情報がありましたら、教えていただけますと大変助かります。
よろしくお願い申し上げます。