I already have a portable 12V cooler that I use for frozen foods.
I have a fairly large space that I can squeeze in a refer so I had to choose a refer that would fit. I came up with a Norcold. DE0788B with 3.1 cu. ft. 12VDC/120VAC combo.
I could have gone bigger but the outside dims would only allow this one to get over the stove.
Also I have this small compartment that has been useful for storing breads. The portable is attached to a larger compartment cover that is hinged. So I had to cut an angle in the lid so it could still be raised with the new refer in place.
The base for the new refer...................
Had to install a 120VAC outlet for the new refer.
I painted the small compartment white for better visibility in the darkness.
Here with the base above the small compartment.
Here with the refer installed.