Billing Displacement: Peter Sellers signed on back when the film was serious. At that point, it was intended to be a vehicle for David Niven. Much rewriting and scene-stealing later, Sellers actually ends up with top billing alongside Ursula Andress.
Creator Killer: A sadly literal instance. The stress of making the film caused producer Charles K. Feldman to develop heart problems, which claimed his life just two years after its release.
A less lethal instance happened to all of the film's directors except for John Huston. All of them had fairly distinguished careers prior to working on this film, but none of them had anywhere near the same success afterwards. Probably the worst affected was Val Guest; after word got out that he had taken over as the primary director late in production, he got unfairly blamed for the resulting mess and was reduced to directing Awful British Sex Comedies for the rest of his career.
In addition to Ursula Andress & Burt Kwouk, another MGM Bond movie alum is in the cast; "Le Chiffre's Representative" is played by the late Vladek Shybal, who also played SPECTRE chessmaster Kronsteen in From Russia with Love.
McLeaned: Evelyn Tremble's death, because Peter Sellers quit/was fired from the film.
Troubled Production: Not only an obscene number of directors and screenwriters got involved, but the actors fought with them.
And the actors fought with each other — the reason that Evelyn Tremble and Le Chiffre are not seen in the same shot during the Baccarat scene is that when they tried to get Peter Sellers and Orson Welles in the same studio, Sellers balked. He felt that Welles was not taking the scene seriously (remember that Sellers had wanted the movie to be the straight adaptation he was promised and was increasingly enraged over the continual slide into wacky parody the script was taking). Sellers was also an extremely superstitious man and took exception to Welles performing magic tricks during shooting, and finally refused to appear at the same time with Welles, forcing their lines to be shot at separate times.
What Could Have Been: The producer had intended to cast Sean Connery as Bond, but balked at the star's paycheck demands ($1 million, which wasn't cheap back then). It is assumed that had Connery been cast, it would have been a straight 007 film rather than the parody it would eventually become. Years later, Connery ran into the producer and told him it would have been much better if he had agreed to the million-dollar paycheck.