Ist it planned to have a feature that allows to automaticaly change the rights on a folder after certain point in time? This features could be interesting if you would like to allow people to make remarks via a discussion on a document until a certain date.
That's an interesting idea. And in Alfresco 1.4 (or SVN HEAD right now!) the JavaScript API is able to modify permissions on a node. So add that to Andy's suggestion and you have your nifty solution