Fans of Mel Brooks's 1968 cult comedy "The Producers" are fairly chomping at the bit over the new musical version set to open on Broadway in April with Nathan Lane and Matthew Broderick in the roles originated on film by Zero Mostel and Gene Wilder. From Chicago, where the stage show within a show (about producing a sure-fire flop called "Springtime for Hitler") is now previewing, the show's creative force, Brooks, told the Los Angeles Times that Dustin Hoffman nearly made his screen debut in the wild farce, as the mad playwright Franz Liebkind (ultimately played by Kenneth Mars). In fact, Hoffman, then a struggling New York actor, "had agreed to do it," said Brooks. "Then one night, I wake up because he's throwing pebbles at my bedroom window. I tell him, 'Hey, I'm not Roxanne. You'll break the glass. What do you want?' " Brooks met Hoffman outside the house and got some amazing news. "You'll never believe this," Brooks said that Hoffman told him, "but Mike Nichols wants me to audition with your wife for a movie he's doing. Will you let me go to Los Angeles for the audition?" Brooks, figuring there was no way Nichols would hire Hoffman, let Dustin go. "Well," recalls Brooks, "he auditions brilliantly, he gets the part, he makes 'The Graduate' with Anne, and the rest is history."