Re: Multiple sites - which package?
WordPress MU, or multi-user, is designed to run thousands of blogs with a single install.
http://mu.wordpress.org/
There are some existing members of the ClassiPress community who have successfully set up their sites to function in the way you are suggesting (although these were set up using previous versions of CP).
This one is a very good example of what I think you're referring to anyway:
http://wpclassipress.com/forum/viewtopic.php?f=3&t=2049
Another thread which may provide more useful information with regards to a MU setup:
http://wpclassipress.com/forum/viewt...&t=2078&p=8807
It is my understanding that the features of the Ultimate licence will make things a lot easier for those who use a MU setup, but without having used it myself I think David would be best explain how this licence works. I will try and get more clarification for you. :)