I was a bit confused where to post this, but here I am.. I have been looking for a simple client/billing system that is compatible with Paypal/2CO. I need it to have the following: - Registration restricted per invitation code - Ability for clients to use a form to get a quote and have the quote sent to admin for approval, which will then become an invoice to be paid. - Clients having access to their control panel of course, viewing their services and invoices. Any ideas if such thing already exists?