This theme if a Xfce port of a KDE theme "MGBerizh" by Mikael Georges.
I've found it on a quite old Knoppix CD and only there. I like it very much, so I've changed it a little bit to make it work with Xfce and here it is! :)
This theme differs from others, so I believe you'll enjoy it. It looks nice with gray, black and white colorsets. I've found a really great style (http://xfce-look.org/content/show.php?content=15444), which suits Berizh Return well.