literally a "furniture van", it's a real box on tracks.
I had to construct four new sides as the original was missing three. There were two styles of side wall one with the top sloping inward and the other just made of a flat plate, so naturally I made the flat plate version. Unfortunately I only discovered to late that the small plates on the front and rear were made to fit the side wall when it was lowered to about 45 degrees, typically I had copied the small plates for the sloped sided version!! Hopefully the camo will hide the error most of the time.
Here's a picture of the original Eidai Mobelwagen as purchased.
In retrospect perhaps it would have been just as easy to build one from scratch on an Airfix panzer IV chassis.