It could be that GM's new Colorado is actually a rebadged Taco body on a GM chasis, both trucks may be built at the NUMI plant in Fremont. It may appear that appear that Toyota is copying GM, since the Colorado was released first.

I always though that the Tundra looked more like an evolved T100 and not a copy of the F150, since the new F150 debued between the T100 and the Tundra(that was going to be badged the T150, but Ford assumed their loyal buyers were to stupid to know the difference and may end up buying a Toyota, so Toyota had to rename the truck).