We are ISV partners looking for a developer to build a social networking platform with the following specs:

1) Subscriptions for Force.com paid "superusers" would be automatically tied to billing/deductions via Paypal or some other payment source.

2) Limited access standard users can sign up for Chatter Free accounts via a publicly accessible website so there is no need to internally "create" an account for just anybody. 

Please include portfolio/links to examples of other Force.com development - preferably Chatter.