What I was thinking was a Mod to make someone a "mega mod" and it essentially added them to all forums. Then when you created a new forum, code would have to be added there to make sure that user was automatically a mod in that forum.
I think this is easier than trying to create a third type of user status - as that would modify MANY scripts and be a PITA to upgrade. Easier to just have a mod that automatically made someone a mod in every forum... and made sure that was always the case.
Option 2 is to make a second type of Administrator - that had restricted admin menu options.
It's been on one of my "when you get a chance" lists for a client.