Many thanks to Jennifer Stott for this information and pictures.

We found a 2.5 cubic foot Frigidare with a lock, at Lowes, that was the same size as the original icebox and required no change in the original opening size. Russ made the wood trim and painted it to match the trim around the cabinets. It was screwed to sides of fridge, the refrigerator Inserted and screwed to "wall"/opening. No handle to get in the way. Even retro Frigidaire writing on it!