The XenLayer Virtualmin theme is based on the original Virtualmin Framed Theme, with some light modifications to colors and buttons to give it a more modern look and feel. It works as a standalone Webmin and Usermin theme as well (install separately).
The theme and screenshots can be found here: http://www.xenlayer.com/xenlayer-theme.html
To install: Webmin > Webmin Configuration > Webmin Themes > Install New Theme
or: Webmin > Usermin Configuration > Usermin Themes > Install New Theme