Denny, I've taken apart those cheapo woodstove thermometers to get at the bimetal before, when I was making a knockoff of a Lionel railroad signal block with thermal train delay. They contain a pretty good size coil of thick bimetal that you can bend to your specification, although you will need to calibrate the circuit breaker you just made out of it somehow. If you want to do a functional replacement maybe you could just use one of the Buss thermal circuit breakers mounted to the frame.
