Well, i'm admin/coder on a fairly large board. (i'm taking large as it needs its own dedicated server)

The way we try to work it is somethign like this:

6 admins; In theory we all have a responsibility such as coding, or dealing with problem members.
5 Smods; some look after a section of the board each, some just float between sections helping out where needed.
about 50 mods; They do most of the day to day grunt work in their indervidual forums.

We've got a custom built warnings system which helps alot with dealing with threads + posts, we also have a forum for each level of staff and a warnigns forum to deposit trash in. Again in theory there should be regular meetings help on Irc between various groups of mods/smods/admins to discuss new policys and other such occurances.

We topped 7000 users recently. We have 12 on our staff right now. I have two "super admins" (myself and one other) who have access to everything, including board configuration. I've learned never to have the full admin responsibility on only one person. Sh-tuff happens. ;) Two others have limited admin privileges--they can edit users, add to the banning options list, and access a few other admin functions. All the rest are super moderators.

We run a completely separate password-protected forum for moderator/admin issues. We used to have our moderator issues in the main forum, but we once had some database corruption in the search index, and our new moderator posts were showing up in search results for ALL members! (Posts were not accessible, but the thread titles were...) In the main forum, we have areas for Problem Threads, Problem Posts (which is now unused due to being able to soft-delete posts), Private Archive (for removed posts or threads that had nothing wrong with them), and a couple other areas. Our private forum has a member issues area, a forum business area (tech issues), a moderator reference area, and a break room to keep all off-topic banter out of the working areas.

Reported posts come via e-mail, since our admin/mod forum is separate from the main forum. We also have a special "911" mailing list for all the moderators, in case the forums are down.

I know we'd like to add a couple more moderators, since I'm thinking we should have maybe one moderator per 500 members.