RE: Tamiya Sand Scorcher, Buggy Champ and Ford F-150 Ranger
The f150's will never be collectable because they were produced in HUGE quantities and use a common chassis with no model-specific parts. Tamiya just recently started producing it again, after only a 5 year hiatus. You can also still find the old model NIP on ebay for retail price.
Oh, my bad. That's what I get for skimming over your post...
I would still build it, but leave it on a shelf.