Hello,
As you may have noticed, Roan, Krinkle and me have started to more tightly integrate image licensing within MediaWiki. Our aim is to create a system where it should be easy to obtain the basic copyright information of an image in a machine readable format, as well as querying images with a certain copyright state (all images copyrighted by User:XY, all images licensed CC-BY-SA, etc)
At this moment we only intend to store author and license information, but nothing stops us from expanding this in the future.
We have put some information in a not so structured way at mw.org [1]. There are some issues open on the talk page [2]. Input is of course welcome, both here or preferably at the talk page.
Bryan
[1] http://www.mediawiki.org/wiki/Files_and_licenses_concept [2] http://www.mediawiki.org/wiki/Talk:Files_and_licenses_concept