Engel MT35 Medium Portable Fridge/Freezer
This is the one I have here in the motor home.. Now being a real compressor freezer it draws some power.. A great whomping 36 watts (Most small freezers take at least 100 if not more) that's 3 amps at 12volts.. Or... less than one headlight.. Works well and will hold frozen even when the ambient is over 90 degrees.. Does warm up if the batteries run down though (This is to be expected)
Norcold has something like it (Though I do not know if it will freeze) you can see it at Camping World or other RV places.