I needed a way to have a customer signup for recurring billing transparently -- my client didnt want them to appear to be registering to a website--rather just subscribing to a service. No username-- no password. I hacked Community Builder, and Account Exp component considerably and I will make those files available once I do some documentation this week.
The files provide for an 'invisible registration' still allowing you to capture customer data VIA virtuemart-- and still getting a full name - and customer data.