Now I see that your sig has a Toyota in it. The Tundra beds are yet another few inches shorter that Dodge/Chevy.
When I see a FP on CL, I usually post it up here. I am currently looking for a friend who needs one for her SB 90's-vintage Ford. There was a flurry of FPs on the used market this summer, but not much lately.
Good luck with your search.
bb