I could probably help administrate to some extent. (The equivalent to a vBulletin "moderator" on MediaWiki would probably be an "administrator". I suspect you can create custom permissions, if you want to keep the terminology consistent—but since the forum moderators aren't necessarily the wiki moderators, it may be best to leave it alone.)
Also, if you plan on integrating vBulletin and MediaWiki, check the code of that extension to make sure it passes login credentials in a secure way. We wouldn't want plain text passwords or anything like that. (I bring this up because that extension
says: "Here is some base code for authenticating. This is not a working example, it is only a starting point.")