That's the second time I have seen that thermostat box in as many days. Over on pelletheads.com, a couple of the guys have put together a customer traeger controller using something that looks pretty much identical to that. No technical details yet, as they obviously want to to prove the concept first.
http://pelletheads.com/index.php?topic=8224.0
Still, I'm also fairly interested in what the cost of the kit would be, but without the battery and blower.