So, I posted this almost a year ago and never updated with the solution I opted for.

There was also a washer and dryer in the area, which weren't being used (they were old and junky). I had someone unhook the 14-2 wiring from the water heater and disable it, and remove the 10-3 or whatever from the electric dryer and connect it to the water heater. He also fixed a few of the other unsafe bits and pieces (unboxed splices and stuff) while he was at it.