Right, but I don't think they'd be compatible with the CAN bus shield I'm going to be using. Plus, I rather like the idea of powering the Arduino board off of the RPi, and having the boards stacked together for a cleaner install. Unless those "a la mode" boards are really expensive or end up getting delayed by months, I think I'll at least give it a shot, as it seems to fit the exact requirements I have for this project.