1 Click Install

Are there any 1 click install scripts for things like wordpress, drupal, etc to offer to customers?

yes it comes with virtualmin pro. it is not 1 click, there are 3 clicks though

what ones does it offer?

are you not allowed to have reseller plans on GPL?

You can see the full list of available Install Scripts here:

http://www.virtualmin.com/documentation/install-scripts

The GPL version of Virtualmin does not have the Reseller feature – you can see a list of differences from the GPL version to the Pro here:

http://www.virtualmin.com/compare.html

Joomla! is missing in the full list of scripts…