Here's an obvious one:
Possibly the most profitable composer of the 20th century, and the most profitable director in Hollywood (I probably crucified myself saying that lol) working together on a movie:
Andrew Lloyd Webber and Steven Spielberg.
They actually came close. Steve was to direct an animated screen-version of CATS, with a screenplay by Tom Stoppard, giving a back-story to the proceedings. Music was scored, and a new song was written, but the project fell through at the eleventh hour.
Since Spielberg is (obviously) searching for musicals, we all know that - especially with Phantom's success to help him now - Lloyd Webber's being trying for a Hollywood career over twenty years. He's been tossing around shows like Aspects of Love, Sunset Boulevard, The Beautiful Game, Starlight Express, a remake of Jesus Christ Superstar, Whistle Down the Wind (originally intended to be a movie) and The Phantom of Manhattan: the continuation of the Phantom of the Opera
Surely Spielberg, an old friend of Webber, would take the hint and scare the pants off of every ileet snob in the universe, sending them running for the hills as their combined force takes over the world and breaks every box office record in the history of mankind LOL. What about Jurassic Park the Musical? Lloyd Webber could recycle VAULTS OF HEAVEN :p
O.K. I better shut up now...
LOL
Who can explain it, who can tell you why?
Fools give you reasons, wise men never try
-South Pacific