Jim,
You could always try the Amish cooling unit for the Norcold.
http://www.ajmadison.com/refrigeration/
I found this site very helpful in looking for a residence type refrigerator. I am not recommending these folks, but their website is one of the best for research. It let you put in your maximum dimensions. BTW on the depth measure your cabinet depth, then subtract 1 inch for back air flow and add 4 inches for the thickness of the door and gasket as an estimate. When you look at a refrigerators dimensions for the depth look at the case depth allowing an inch at the back for airflow.
I was mostly limited do to height restriction because my unit is in the slide and Sheila did not want to lose the drawer underneath.
The other thing to watch is the estimated energy use.
If I can help in your search let me know.
good luck,
ken