A local guy with a semi-sorta restored A coupe - Miller head, full pressure oil, pair of 81's - used an A/C unit out of a Ford Windstar.

He mounted it under the package shelf and a little way into the trunk.
Worked good and the controls beside the driver and having to reach around to get them wasn't too bad a deal.

It sure kept the resto flavor of the A and he was able to cruise on 100 degree + days.