One of my favourite GTK themes of all time was Elegant Cold Blue, a spin-off of Elegant Brit. I’ve decided to have a crack at porting it to Xubuntu 12.10. Along the way I’ve been able to make a few tweaks to the theme to make it more usable in xfce by utilising elements of Xubuntu’s default theme: Greybird. For a similar theme on Ubuntu checkout Elegant-Ambiance or Milieu Bird.
To use the theme on Xubuntu first create a .themes in your home directory. Unpack the Elegant Bird folder to here. When you run the Settings Manager the theme will now appear in the Appearance, Notifications and Windows Manager settings. Changing to the theme through the settings manager will update the changes (though you may need to log out and back in again to finalize the changeover).
The theme was built for (and tested with) Xubuntu 12.10. The theme should work with other versions of Ubuntu but may need a bit of tweaking to look right. I was tempted to use the googol buttons I’ve used previously to make things more colourful but decided it was best to keep the theme looking tidy. Feel free to modify and redistribute since the theme, and those it was built on, are licensed under GPL.