We'd like to modify our version of MediaWiki (currently running 1.4.x, but soon to upgrade to 1.5) so that the skin will display differently depending on the content of the page. For example, if the source code of page "Foo" contains the text "{{template:bar}}", page "Foo" would show a different site logo than other pages on the site, or it would use a different CSS stylesheet.
Is there an existing way to do this? If not, can someone point me to the spot in the codebase where we should look if we need to hack this ourselves?
--Sheldon