RedFive said:
Yojimbo (1961), A Fistful of Dollars (1964), Last Man Standing (1996)
So "Last Man Standing" is a remake of "Yojimbo," which had an uncredited remake in "Fistful" and is itself an uncredited adaption of the novel "Red Harvest" which has to be unique in all novels as having three adaptations, none of them official.
I hope someday "Red Harvest" gets made and everyone says "This movie is a rip of of 'Last Man Standing!'"
EDIT
Even kookier, but I haven't seen it, supposedly Yojimbo was also remade as The Warrior and the Sorceress with David Carradine.