You may have heard that Something's Got to Give, the picture Marilyn Monroe never finished, was supposed to be directed by Frank Tashlin. He had written the script, but Monroe refused to work with Tashlin, and insisted that a new script be written and that George Cukor be brought in to direct. This was undoubtedly one of the things Tashlin was thinking about when he told Mike Barrier that "many actors have turned me down, wouldn't allow me to direct them."
But what I hadn't realized before was that Something's Got to Give was originally supposed to be a vehicle for Jayne Mansfield. In a letter to her fan club in 1961, Mansfield wrote that her next picture would be Something's Got to Give:
I may do a movie called "Something's Got to Give" on location in Hawaii. At the present time we are involved in finding a leading man and ironing out all the technical difficulties that go with the production of a movie. Frank Tashlin, who wrote "Will Success Spoil Rock Hunter" is writing the screen play and will direct. It is actually a remake of a hit a few years back called "My Favorite Wife". I like the script very much and it should be a great picture.
Apparently Joan Collins would have been cast in the role of the other wife (the role that was to be played by Cyd Charisse in the Monroe version). Though with that cast it would undoubtedly have been less than a grade-A Fox project, I have to say it's too bad that a Tashlin-Mansfield reunion never came about.
As for being fired off the Monroe version, apart from anything else, I don't think at that point Monroe would have been very compatible with him; she really seemed to have lost her taste for outlandish, cartoonish comedy. A hint of that is that when she submitted her list of acceptable replacements for Tashlin (with the names of Billy Wilder, Vittorio De Sica and others in addition to Cukor, who was available), it didn't include Howard Hawks, whose Gentlemen Prefer Blondes was an admitted influence on Tashlin's Jayne Mansfield films.