John Malkovich has heavily hinted on an Italian sports show (of all places) that he has been offered the role of the Vulture in Spider-Man 4. But with the delay in production due to script rewrites demanded by Sony, it's unclear if we'll ever actually see him in the film.
According to Coming Soon which has translated a report on Italian site Bad Taste.it : "When presenter Simona Ventura asked him about his role of Vulture in the movie, he not only didn't deny his involvement, but confirmed that he's waiting for the final script to be sent to him, and that the movie has been delayed. He also hopes that shooting will begin as soon as possible."
He would make a great Vulture, but we'll have to wait and see if Sony lets Sam Raimi use that character in the film. Allegedly, the company was unhappy with a "winged" villain. But, hey, it might fool a few Twilight fans into buying tickets if they mis-hear him as "The Volturi".