*"I think Stallone could have done it. It wouldn't have been Marlon, but I think he can act and he's physically perfect for the part." Sidney Lumet on what was almost his next project, a remake of a "A Streetcar Named Desire," with Sylvester Stallone as Stanley Kowalski. The project foundered when Vanessa Redgrave turned down the role of Blanche Dubois . . .

*A reason to wait till next year: Henry Fonda will return to the Washington stage sometime in early 1982. He is scheduled to appear at the Kennedy Center as Harry Hopkins in David Rintel's new play "World War II." John Houseman is directing. Uncast are the roles of FDR, Stalin and Churchill . . .

*Pop Note: Jimmy Page, Led Zeppelin lead guitarist, will compose the score for Michael Winner's film "Death Wish 2". . .

*Coming up: In late October, Al Pacino, who has been packing them in Off-Broadway in "American Buffalo," will be shooting a comedy called "Author, Author" in New York, New York . . . Michael O'Keefe (he beat Robert Duvall in one-on-one in the "Great Santini") will be replacing Richard Thomas for four weeks in "The Fifth of July." Reason: Thomas is taking paternity leave. His wife, Alma, had triplets last Wednesday . . . Joseph Papp will direct something called "Fresh Fruit" by Kid Creole on Broadway . . .

*Not coming up: Variety lists several major films languishing and expected to remain on the shelf: Ryan O'Neal starring in "Green Ice," shot in 1980; Ellen Burstyn and Tom Skerritt in "Silence of the North," shot in Canada in 1979; and Richard Jordan, David Niven and Gloria Grahame in "A Nightingale Sang in Berkeley Square," also shot in 1979 . . .