If the Rams don't have a first round pick, you simply tell them sorry, Payton isn't available to you. Tough luck. Chargers...I'm inclined to think Staley stays put unless they miss the playoffs and/or lose games. Cards, they're not making another coaching change just yet imo. Dallas? McCarthy ain't going anywhere just yet. They've had a nice season, although they're only a couple of losses from being out of the playoffs.
I'm not sure Payton and the Steelers' culture would mesh. But they do have a young qb to groom.