I'll vouch for the vintage Coleman icebox. Five-dollar flea market find, and one homemade block of ice will last us an entire long weekend. We keep drinks in a separate cooler, and everything else - meats, dairy, etc. in the icebox.
There is some insulation around the surrounding cabinet in our galley, but I don't think it needs it, frankly. We'll have a about a quarter of the original ice block left when we get home from a long weekend trip. Love this thing.

In the wild:
