I was at a Q and A for Death Proof a couple of years ago, and he talked about that. His plan was to do Casino Royale with Pierce Brosnan, and to do it in black and white with Uma Thurman as Vesper.
He figured that he could do it for 35 million and that even the least successful Bond movies had made more than that. He reckoned that it could be Brosnan's last movie and EON could bring in a new actor and get back to normal with the next movie.
It obviously didn't happen.
Spielberg lobbied for a Bond gig in the 70's (after Jaws). Cubby Broccolli didn't want him at the time. When Spielberg got more successful, they wanted him, but they couldn't afford him.
Apparently the idea for him directing Indiana Jones came from Spielberg complaining to George Lucas that he had lost out on the Bond directing gig.