Sadly I'm out of warranty.
You are allowing for the warranty being 3 years, yes? If so, I think it died from loneliness having only been used 12 times.
I totally would have expected it to be the cord, but you've said you looked it over pretty close and couldn't find any problems with it. I haven't ever opened one up to know if anything I say here is impractical, so take everything with that grain of salt. In each case I'm assuming you're starting from where you are right now and that you have it unplugged except when absolutely necessary.
Some things you might try if you don't have a meter:
* Disconnect the power cable where it hooks up internally. Tape off the individual wires and then plug in the cord. If the breaker still trips then it's the power cable.
* Disconnect the element and see if it still trips when you plug it in. If it doesn't then it's probably the element.
* Disconnect the rheostat and 'hot-wire' it. Plug in briefly and see if the element starts to heat. Unplug right after since there is no temp control at this point and don't want to damage your smoker.
I would still be tempted to send Steve a note... I would be surprised if he didn't give you more troubleshooting ideas. Fortunately, the parts on the #2 are relatively cheap and the smoker relatively uncomplicated. It shouldn't take heroics to get you up and running again.