Rob,
You have an interesting problem.
I just went through my documentation and it looks like there is no easy way to determine whether the failure is the electrode or the control board. The fact that it will restart the same cycle after a short power down would make believe that it is the electrode as it serves as the flame sensor and it sounds as thought that is not happening on the re-lights.
The gasket for the door to access the electrode looks to be flat and you should be able to find appropriate gasket material locally. Electrodes are nothing special, just a piece of stainless steel in a ceramic holder. I have even purchase universal cut to fit. But before you do anything else, check the electrical connections to it. I recall once have a bad connection and the burner would light and then shut down on "no flame" some time later when the connection cooled off.
I wish you the best of luck an hope that the blasted thing fails solidly so it can be effectively diagnosed. I hate intermittents.
Matt
Matt & Mary Colie
A sailor, his bride and their black dogs (one dear dog is waiting for us at the bridge) going to see some dry places that have Geocaches in a coach made the year we married.