I just found a fantastic theme for webmin!
You can find it here: https://github.com/qooob/authentic-theme
Finally some fresh dress for webmin, that with default theme it looks like very old!
If you don’t know how to install webmin theme you have to go to:
Webmin->Webmin Configuration->Webmin Themes->Install themes->From ftp or http URL
and paste url link of theme:
For use it you have to be almost with webmin 1.730 and you have to install perl libraries with:
apt-get install libwww-perl
For me it’s the best theme until now.
PS: You can also have a look at theme.winfuture.it that it seem to be also a good theme but i didn’t try it yet.