Link: https://code.launchpad.net/~edb/quam-plures/multiple_admin_templates
We started with multiple admin skins and it was bad because the actual bits changed, sometimes in ways that made tasks impossible. So we ripped all that out. Then we got the bright idea to bring back admin templates as style sheets only. This branch does that.
UPDATE: branch merged into core on 2011-02-11. Incomparable!
