Hi Bobo
We offer a new 3rd party gateway system over at Pennywize, called Pennywize Payments:
http://www.pennywizepayments.com
Essentially it is a gateway which interfaces to any 3rd party bank or institution, and processes charges on your behalf. Admittedly, it's been written for high volume, high-risk international merchants processing offshore, but could be used with US merchant accounts. Also, it interfaces with any number of 3rd party fraud screening companies :-)
It manages all your membership stuff, your rebills, and gives you nice reports and customer services interfaces.
We are really going to start promoting the product early next year (mostly to international merchants) and for any large volume US customers.
Give me a bell if I can offer you any more information
Steve
PennywizePayments.com