I spotted this at our state fairgrounds during a horse show. It's a bit rough but pretty cool. Looks like the front part swings out for engine work. The back and side doors had hydraulic rams to open and close them. You can see the pump under the back.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio