Well, I tried two different CANBus sniffers, and there was too much noise on the line for either to work. I’m going to see if I can isolate the noise (one guess: the controller), but still not holding out much hope.
On the good news: I’m in touch with Paul of http://www.paulandsabrinasevstuff.com fame. They have a beta AC controller designed, and I think I will give it a shot. Certainly better than nothing.