I'm desperately looking for a bed liner and bed cap/shell for my '86 pickup extracab. The bed of my truck measures apx 77 × 60". My question is:

1)Does anyone have a suggestion for where to look for these things besides FB marketplace, Craigslist, etc?
2)What are some trucks with comparable bed sizes that I can search for? My thought is if I can find something close enough I might be able to jimmy-rig it to fit.

Any help is greatly appreciated! Thanks in advance!