Could you potentially install a remote bleeder under the back seat or in a compartment or something? If you had a long enough hose, and you opened the end of it, I would assume the air trapped in the system would come up to the end of the hose, and water will fill the hose up to the pump level. Not the best solution, but perhaps a possibility.

Yep! I have told boaters with big cruisers to try things like that when they complain about having to go down into the bilge area to crack the hose off the pump to bleed the air out....just install a "T" fitting on the outlet of the pump with the straight though part connected tot he outlet of the pump and to the bleeder valve.....the side port would go off to your AC unit....if its locked up crack the valve let the air out and close it off again and you back in business without any sweat :)