Would you consider William Munny an allusion to all of Clint's earlier bad-asses?
An older version of TMWNN filled with guilt and/or regret......, I feel that way. When Unforgiven was over we were leaving the theater and two older guys I was walking past commented on how that was the worst Eastwood movie they ever saw.
They obviously wanted a Leone film.
Sticking with Eastwood:
Kelly's Heroes had that showdown bit referencing the Good, the Bad, and the Ugly.
Dirty Harry had the movie Play Misty For Me on the theater marquee in the background.