These Dometic Fridge/Freezer are excellent. The CFX 28 fits between the two middle seat in the 6 seater or fit in the rear trunk behind the 3rd row seat. They rarely go on sale, but you can get them now for a slight discount. The stock 12v cuts out everytime the car shuts off, so its good to get a cheap battery pack. You can run this for a few hours with a portable battery that you can charge on the fly.
Dometic CFX 28 Electric Powered Cooler: Never Use Ice Again
Dometic CFX 28 Electric Powered Cooler: Never Use Ice Again