Very cool build! My grandfather did something somewhat similar years ago. In 1983 he purchased a brand new Chevrolet P30 motorhome chassis with a 6.2L diesel and TH400 tranmission; just a chassis with no body. He then scoured the salvage yards looking for body ideas. He ended up taking a Dodge full-size van and cutting it down in length to make a cab, took two Chevy square-body beds to make a wider fleetside bed to cover the dually axle (he didn't want fender flares like on traditional dually beds), and then filled in the gaps with various other body parts, including Ford Escort headlights, a Pontiac grille, custom-made hood, and custom-made wind deflectors. It was quite an aerodynamic rig for 1980's standards.
Casey