Regarding the ShunAuto link, here is a quote regarding one option for a homemade HiLo trailer chassis: "The Freightliner Custom Chassis S2RV is a strong and reliable option, known for its commercial roots and durability. It evokes the feeling of driving a commercial truck, with its diesel engine and sloping hood."
As the owner of a monster diesel pusher on a similar Freightliner Custom Chassis, I would not recommend this starting point. Many other outlandish ideas are found in the article -- AI generated? [Note to serious people: the ChatGPT summary is very incomplete.]
HiLo is dormant and has been for a long time. Even if the family who owns the name (and that's all) finds an unsophisticated investor (goal of the cited website), the HiLo materials of construction are wrong for an offroad application.
Here is the value prop of our rig to a builder: ours was made in approx. year 45 of the company's history -- they perfected many things over these 45 years.
