Multisite

I am sure there is an answer somewhere, I just cannot find it.

Here is what I want to achieve, by either coding or simple plugin.

I have multisite setup, and I would like to easily allow my employees to login, and create a new site on the fly without having to enable/select a theme and create pages.

I want one page and one theme, already setup and that one page and theme to be used as the default. Basically, all they will have to do is login, add site, then just add the content, and publish.