I knew of the style differences between brands, and expected to replace it with a new Suburban (bonus - they're cheaper anyways!). Extending wiring and gas lines are simple if need be, especially compared to changing the opening size.
I did take a closer look at it yesterday, and was able to easily punch a small screwdriver through the crud, which let all the water drain out. I also noticed that it didn't actually break the drain tube, but did mangle the first thread or two so that I couldn't just screw a new fitting on. The tube appears to have a pretty thick wall compared to typical plumbing pipe, and I'm thinking I may be able to run a pipe tap into it and just use a NPT plug to seal it off if I can't get the threads cleaned up on the outside.
It's definitely not an anode, or the remnants of one. The drain valve on it has a rubber disc that's connected to a screw on the inside, with a hole drilled on the side of the valve. The valve screws on to the end of the drain tube, then the inner screw is run in to press the rubber disc up against the end of the drain tube. Run the screw back out, the disc retracts, and the tank water drains out of the little hole.
I looked at new anodes at the RV parts store, and there's no good way that I can see to retrofit one either.
