For reference, you can use the Ambiance Crunchy set of themes. [1]
Recently, it's been updated for GTK+ 3.8, and it still uses Unico. It looks fine in the current beta of Ubuntu Saucy (so, please, no "theming is totally broken" arguments) which uses the latest build of gtk3-engines-unico.
I suggest updating gtk3-engines-unico to the same version (revision 150). It's not that hard.
[1] http://box-look.org/content/show.php/?content=136162 -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
