Around 2001 or so, we mounted a sixteen-foot box on our 1984 Peterbilt cabover.
Prior to our acquisition, the rig was operated by a moving company. It had the largest sleeper... plus a 8x8 condo. With a 276" wheelbase, it devoured parking-lots.
Every rig is a stage in evolution. Our current rig is a 1997 Ford CF8000 with a 176" wheelbase. It's handier in tight situations. We did south America twenty-four months twenty-four thousand miles. Alaska Panama, all over north America. It serves us well... and is constantly evolving.