[ValkyrieSkies]

I've always liked the SS13 model of an administrative sub-forum with sub-forums for:

Ban Appeals (with a sub-forum for closed appeals)
Ban Requests (for formally reporting major transgressions)
Player Feedback (for rulebreaking/misconduct that isn't banworthy but still not cool)
Admin Feedback (A thread for every admin/mod for reporting very good conduct or for judgements that players don't entirely agree with)

It's clean, it's open, and allows easy access to information. Here's the /vg/station sub-forum for example; http://ss13.moe/forum/viewforum.php?f=5 (May contain strong language in some threads)