As the story points out, it wasn't original material when Eastwood and Leone transformed it (though it is hardly a "shot-for-shot remake" of Yojimbo), and it wasn't original when Kurosawa filmed his version. Both movies are more or less directly derived from Red Harvest by Dashiell Hammett, and some would trace the line all the way back to Carlo Goldoni's Il servitore di due padroni, circa 1745 ... rather tenuously if you ask me.
At any rate, there has already been one attempt at a "contemporary, original retelling of the story" ... Last Man Standing (1996), written and directed by Walter Hill. It is a credited remake of Yojimbo.