I had set it up so that only logins in the group 'editors' could change the article text but allowed all logins to edit the talk pages, however management want me to add a system so that changes to the 'article' page are approved before they are visible to everyone. This goes against the ethos of the wiki I know, but all our users find the wiki very easy to use to find things in and appreciate the ability to add to the talk pages.
Accepting that I'm going to have to do this, or move the whole lot into something else and loose the advantages of the wiki for users, I would appreciate comments on the following approach.
I would have two special groups of users, 'editors' and 'approvers'
Take a look at this: http://svn.wikimedia.org/viewvc/mediawiki/trunk/extensions/StableVersion /
It doesn't do exactly what you want, but it gets pretty close. There are of course holes in this like every other protection scheme for MediaWiki. For instance, users could use page transclusion to see the newest version... However, what you proposed would allow that as well.
In the above extension, notice how things are done for anonymous users, and apply that to users with specific groups. If you can make it generic enough, I'm sure Magnus wouldn't mind getting a patch.
Btw, after MediaWiki adds versioning stuff in the future (1.10 is it?), I'm not sure how much development work will be done on this extension (as that was the original purpose of the extension).
V/r,
Ryan Lane