This is just a head's up that I had everything working under Virtualmin GPL (took a day or two to get working), and the move to Virtualmin Pro was an absolute breeze. (Kinda wondering why all the warnings, honestly...but then I've written modules for Webmin in the past too...)
Anyway, that said, frames are hellspawn. :) The larger part of my time setting up Virtualmin GPL was getting a theme going that didn't make me want to gag. ;)
So...here's what I have come up with. I have taken and modified the "StressFree" theme, created a custom index.cgi, and modifed theme.pl to include many elements that originally lived in left.cgi. I copied over edit_right.cgi to the streefree theme directory, and copied over the lang subdirectory of the virtualmin theme. That's it! :D
Don't know if anyone else feels like trying it and and maybe helping me clean it up, but it's working out nicely here.
Again, awesome product, dead simple install on FreeBSD, absolutely no issues at all.