The Wikimedia Foundation per se doesn't have
incentive or a goal to
rebuild MediaWiki as something in which real security is a design goal
right now. Which is somewhat unfortunate, as some commercial and
organizational users could use that. The CIA did, but we didn't get
the code.
I think you are confused on what Intellipedia's classification system does.
Though the classification system they have is nice, it would be really easy
to replicate (and probably in a slightly better way). It isn't page level
ACLs, or anything like that.
Respectfully,
Ryan Lane