Look at truckfridge as they have modern 12v compressor fridges that could work in that space and not require the same amount of venting that a typical RV 3-way fridge would need. They need some venting but I bet you could do that to the front of the cabinet rather than going through the outer skin. Not many would see the vent behind the seat.
These are awesome, thank you!
Is there trim strip pc. missing? ,they cover the screws so the water don't get in
Yes, I have some leftover from my last project. Going to install it this week.