Synopsis: <IfDenied> directive wanted State-Changed-From-To: open-analyzed State-Changed-By: marc State-Changed-When: Fri Jun 26 09:31:22 PDT 1998 State-Changed-Why: The example you give is already possible just using the Satisfy directive.
The whole authentication and access control language needs a rewrite, and that may happen in 2.0. We don't really want to add a zillion hacks to it though in 1.3 and make it more of a mess...