Maybe give people in power the ability to reward for good posts (as in, cash bonus) and smite for bad posts (deduct money). Give people what they like, and hit them where it hurts. Along with infractions, of course. Or maybe make it so that an infraction pulls away X amount of money from the infracted person? While it's certainly more whip than carrot, it might make people think twice before posting like, pardon me, idiots. Sure, getting infracted/banned is nasty, but an added monetary penalty would make it even nastier. Along with a reward-button, this might encourage good posts. There's undoubtably some flaws in it SOMEWHERE, but honestly, which strategy hasn't? >.>
In short, maybe make infractions/bans deduct TC from the perpetrator, and maybe give people in power a reward button. In case of rich people being able to "afford" being infracted, maybe a percentage removed instead of a fixed amount.