Dad  worked up a couple poly prototypes in the late 70's  to test  the  pickup market.     By the time he got it strong enough to meet his criteria (It was going to carry his logo after all)  Henke Mfg- it was actually  heavier than an all steel unit..  and unfortunately, more expensive.
His all-steel ones were bad enough- I remember him shaking his head when another happy customer drove off the place with a half ton pickup squished down to the bumper stops..
   No matter,  the heavy snows in the late 70's and early 80's  keep them busy enough with the big stuff.