cRiPpLe_rOoStEr
We don't ride to provide a good story for the rice
GM had the PROTEC composite plastic bed for several years in the GMT 800's, and Toyota's beds are all composite on their Tacomas. The claimed weight savings and "durability" will hit all manufacturers some day.
Weight savings can be a reasonable argument, but durability will depend on the composites used to make the bed. Fiberglass-reinforced plastic is actually a good option, for example, and GM has a lot of expertise with this material...


