I've got factory A/C in both 1 tonner and panel van project, but I once explored dual zones in the van and my A/C shop suggested adding an aftermarket box to the rear of the van in the void panels and then pushing 4 x ducted vents to different spots in the back. The front would use the factory air and the back would run separate. I wanted it to run when parked up but couldn't figure out a suitable electric compressor solution.

AC Box.jpg