Nordost claims they are on a path to have them. This is a long, almost one hour presentation. But worth a look. Skip the early junk about math and such. It is all non-sense as there is no "math" involved in anything they measured or talk about.
http://audiofest.net/2010/video_player.php?video_id=10&Sid=10c06a43bf211482677cce015fb162ea
http://audiofest.net/2010/video_player.php?video_id=10&Sid=10c06a43bf211482677cce015fb162ea