Great story on Rolling Stone: Bob Dylan wanted to record an album with the Beatles and the Rolling Stones. Andy Green, quoting producer Glyn Johns:
“Keith and George thought it was fantastic,” he writes. “But they would since they were both huge Dylan fans. Ringo, Charlie and Bill were amicable to the idea as long as everyone else was interested. John didn’t say a flat no, but he wasn’t that interested. Paul and Mick both said absolutely not.”
It might have been great, but even putting aside the famous Beatles/Stones rivalry there was no way it would have happened in 1969. By then the Beatles could barely collaborate with each other.
Via the Guardian.