Dan,

There are some third-party extensions that provide some of these features, but they are all insecure and easily cracked.

Just out of curiosity can you point out which extensions are you talking about?

Good news: You can approximate some of these things with the FlaggedRevs extension, which is fully supported in MediaWiki. It hides changes from being seen until a reviewer approves them. http://www.mediawiki.org/wiki/Flagged_Revisions

Interesting. I will take a look at it.

you can't completely hide the changes (they're just not displayed by default), but you do get notification and managers.

Let me explain little bit more clearly in case I was not in my original post. I am not looking to hide the changes. What we really want is once a article is posted to a particular category it is locked down and only few people (who are a part of special group, let's just call "manager") can modify it.

Another way to achieve this would be to put a lock on an entire category so that only users in the "manager" group can post the article in that category and once it is posted it is locked down.

Thanks for your input!