Watching the extras on a DVD can be so enlightening. On "Stranger Than Fiction," Emma Thompson said she read the first 4 pages of the script and knew she wanted to do it.
I've heard other actors (and directors) make similar comments... that they read the first 5 or 10 pages and knew they wanted to do it.
This just emphasizes the need to make the first few pages absolutely shine. To make them clean and clever. To introduce the main characters quickly. To have a strong hook... and, I think, a voice of your own.
Go back and look at your first 4 or 5 pages. Are they good enough to get your A-list choices to jump at the chance to do this movie? (I've re-written the first ten pages of both of mine several times now.)