I would guess that LA will see arena or amphitheater, not stadium, shows. AT&T Park and Yankee Stadium, maybe. A number of smaller markets as well, but I'm not sure how many they're going to hit.
What would be a good mainstage possible subheadliner to play the time slot before the Stones?
Blur OR Stone Roses could work.
There's several rumoured 2013 acts that would be a BAAAD fit. Wu-Tang, Culture Club or Daft fans all fighting for a spot near the stage would be quite funny to watch. The DFA79/Duran/Strokes/Kanye crowd transitions were quite weird.