I am trying to find out what the box on the back of the Rig is called or who makes them. It looks like a small sleeper but has a swing up door and used as a container?

 

Looks like a smaller version of what was called a "Drom" box (dromedary) back in the 60's 70's 80's on semis.
They looked a bit like a small Pantech (box body) with the barn doors mounted side ways behind the cab.
Found this by Googling dromedary boxes.
http://joplintrailer.com/?page_id=260