I am looking at creating a small online community (with a non-technical niche theme).

I will require the following:

A good CMS (Joomla/Mambo/PHPNuke/PostNuke etc)
A good BB (PHPBB, Invision or whatever)
The ability for registered users to be able to automatically create one mailing list each (preferably with a max number of recipients defined by me), where any old Joe Bloggs can choose to sign up to that users mailing list via email, or web page, and to have the mailing list locked down so that any posts to it are moderated, and the list owner should be unable to toggle the moderation feature.
A single registration and sign-on system for the above
A banner ad system with at least basic tracking/stats

Can anyone recommend a web host capable of all this? I would prefer someone like kiwiwebhost who has all these scripts installed already, although they limited users to 20 mailing lists unless I pay for a lifetime of hosting (thousands of dollars). I wont need a huge amount of space, but I will need lots of mailing lists - potentially hundreds within six to twelve months, though they will ALL be low traffic (5 - 50 members per list and 1 - 5 posts per month).

Any other options or suggestions will be taken into consideration. I can see a niche for what I want to do, but it will basically be a community contribution from me, and I do not expect it to be a runaway commercial success (its very niche, and the only expected revenue is advertising or a sponsor to cover hosting/domain name costs)

To clarify the mailing list requirements, I want to be the overall admin, and lock down settings. I want a user to be able to sign up and create a list without intervention by me (and choose a name for it, like joes.list@tonys-domain.com). The creator of the list should have access only to change subscription settings etc, not to have access to toggle moderation and other advanced features.