- Allow the collection of new data for a list of potential clients from web forms (site currently has a popup-to-email way of gathering new signups) or from some similar process

- Allows the indexing of that list data, to be searched and categorised at will from an admin backend.

- Allow the emailing of specific groups, based on shared variables such as "email everyone under the age of 30" or "email everyone who came to the seminar" (so requires the ability to add custom variables to people in list)

- Has some sort of billing module, whereby clients and potential clients can be administrated with reference to the list data.

I am asking for the impossible? I would rather not make this myself..!

Many thanks in advance for any kind replies.