No lie, this took me less than 5 minutes total from first cutting to complete and painted.
Take a piece of 1x2 Tuf Board. Set your mitre box to 22 1/2 degrees (its a preset on mine). Cut a piece 2 3/8" (long side). Take some 040 styrene, mark and cut the roof a bit larger than the top. Glue in place. Cut a door about 1/8" smaller than the front of the cabinet. Scribe in the middle, and glue in place. Cut some styrene scrap for ‘hinges’ and attach. Mark door by hinges, and handles, with rivets. Paint with fast drying aluminum paint. Additional details could include handles made from staples, and some lift rings on the front of the cabinet. Dont forget some 1x2 painted like concrete for a base.