There was, of course, a planned film of Follies years ago, and I believe Debbie Reynolds (and maybe Shirley MacLaine, IIRC) were announced as two of the stars.
RATM had several fun threads about this last year where we picked "golden era" stars of certain studios to cast the potential film.
Paramount, of course, was my favorite. I think FF & Leif would have made a great Phyllis/Ben. BK's recent dinner guest Marsha Hunt would be a great Sally (don't know if she sang, but she has the persona for that role).