I think the people saying Cabot Links and Lost Farm (and Renaissance) are missing the OP's point. He's looking for gems in the rough, not gems that haven't made the rankings yet because they are too new.
I have yet to play, but is there a top 100 course under Cobb's Creek?
Of the courses I've played, the one that screams "a few tweaks from genius" is Michigan, though I could probably make an argument for Bethpage's Red and Green courses as well.
On the other hand, Danang Golf Club in Vietnam is just "wider fairways" away from being great, but I am not sure this can be done as a "tweak" given the massive bluffs Norman massaged.