Modeling chocolate panels make a great looking cardboard, and a strip of piping gel over it looks just like packing tape. Open flaps will require some additional structure though. Oh, and mini marshmallows make great "packing peanuts". When I made the cake below for a friend's going away party, I had at least 6 people rush over and tell me that "someone set a box on the cake" - LOL!
6/17/13 at 7:08pm