And when hidden, maybe a "Show moderation bar" to the right, hanging off the top (same as when logged out) just in case someone wants to see old reports.
Advantage = a cleaner layout for mods, not taking up space when it isn't needed.
I think we've implemented this as far as we will, now.
We've opted to not hide the moderator bar in any situation because for admins there will always be an "Admin" link there and for moderators there will always be a "Moderator" menu there.
Unless there are active items (e.g. Reports and Approval queue) these links will be hidden behind the Moderator menu. The Moderator menu itself might be something that add-on developers wish to utilise for their add-ons.