Dennis Coates' post considered the serious nature of the Saints' bounty system and foreshadowed the stunning response by the league that is now the buzz of sports websites and blogs of all sorts. While the length of Payton's ban surprised me, I'm totally in agreement with the league's strong statement and incentive given not only the program's existence but the coverup by Payton and others, and, even more so, the continuation of the program -- see Head Shots, Part of the Game?
How widespread are such systems among other teams? That question lingers, especially among Saints fans. Although retired players have suggested widespread bounty systems, the NFL's own investigation has not turned up anything as ingrained and easy to track as the Saints'. Of course, the NFL uncovered the Saints' system only with persistence in rooting out the facts, so one wonders if the "don't see other situations like this" response by the league speaks more to investigative efforts on these other situations rather than their non-existence.
One step beyond the question of explicit reward systems among other teams is the issue of implicit rewards for violent play and putting people out of games. Do excessively violent players receive compensation in their salaries over time? Did Rodney Harrison's pay, in part, include a bonus for his intimidating or injuring hits? It's not an easy question to investigate because no violent hit index by player exists (football needs its sabermetricians!). Further, the impact of such an index would have to be separated from the impact of defensive performance (tackles, interceptions, points, yards, ...).