Have you been talking to Gilbert? (I think the answer's "yes" but I want to make sure).
The new, modernistic way to provide a service such as Gilbert suggests in his very first post in this thread is to hook into the new service contract mechanism. Make the cybercash, authorize.net and PayPal (despite its limitations there will be users who want to use it) packages that fulfill the contract requirements of e-commerce. Assuming this is generalized sufficiently then other packages could use the same contract and use any of the given gateways without our needing to rework them.
