Hi Mark,
As far as I know, this is not possible. But, it is possible for you to create a portal template which a user could load using the site wizard. This would pre-load modules, skins and data that you specify.
I've just created a tutorial on this for issue 17 which i am currently in the middle of releasing, but in the meantime, you can view the tutorial here:
DotNetNuke Portal Templates and the Site Wizard
Thanks,