Just to let you know that I've packaged Greybird theme (an Xfce theme from Shimmer project) for fedora 17+, after the installation and activation your Xfce desktop should look to something like this screenshot (from Xfce.org): 
Installation:
yum install greybird-*
Edit:
Here's an actual screenshot of Fedora 17 Xfce with Greybird theme and elementary Dark icons:
