This is my further work on Clutter and Rhythmbox just this time it is actually supposed to do something useful. At least more useful than just spinning that red hand endlessly ;P Fetching covers is done by transplanted API from the original Cover Art by James Livingstone - GUI is Clutter powered of course.
So that's basically it, not mentioning that half of the Cover Art API still remains unclear to me as I have focused on getting the appropriate clutter stage background color. Still, the way it's done is hackish so must be redone.
You need python-clutter package to run this, source code is available via subversion from
svn checkout http://coverartclutter.googlecode.com/svn/trunk/ coverartclutter