I had to build my own on a harbor freight frame. My truck was costing me too much to drive, F350 dually. Its 10'l x 4'w x 3'h and clamp shell type top opening. Weighs less than 500lbs fully loaded for flying and is towed with a honda civic. I still get 27mpg while I'm towing the trailer and 31mpg without the trailer. Cost me about $650 to build. The suspension is too stiff but not any worse than my truck. Later I can get a torsion bar axle to soften it up some.
Edwin