While Robert Downey Jr. and Gwyneth Paltrow can't play Tony Stark and Pepper Potts forever, who are the actors who can replace them? And could it happen after the next Iron Man movie?

With talk of a smaller role for Iron Man in the new Avengers film and actor Robert Downey Jr.'s personal issues, a new Iron Man 4 film is looking less likely by the day.

Iron Man 4 is looking less and less likely, at least with Robert Downey, Jr. as the title character. After saying he might be getting too old for to play Tony Stark, now it seems likely his role may have been reduced in the upcoming Avengers: Age of Ultron.

Could Iron Man 4 include a visit from the one and only Hulk? Iron Man 3 ended with a special scene between Bruce Banner (The Hulk) and Tony Stark (Iron Man) leading into a good opening for the Hulk to appear in the next film.