Ali was, at one point matched against Jim Kelly for an exhibition fight, but for various reasons it never happened. That would have been an interesting match.
Bruce said that for punching and timing he was a huge admirer of western boxing, as arguably the greatest exponent of queensbury rules, it is not so strange that Ali should display many of the aspects of the art that Bruce distilled into his style. Maybe the question should be, Bruce Lee...A flyweight boxer? Would have been great to see him fight within that environment, his speed and timing would have made him pretty good IMO