Salesforce Pattern for Subscription: is the Opportunity the right place

Thanks both of you for your answers.

We ended up getting a presentation from the SFDC architecture team that demonstrated their internal Renewals implementation.

For those curious: they leveraged the Order object being released in Spring 2014, powered by the opportunity (with a layer of versioned quotes on top).

So the Opp is created a year in advance. Quotes are used to adjust the value of the opportunity and get approval both from customers and internally. At time of invoice, the Contract is created along with an Order (and associated Order line-items).

It appears that the Order is then sent to the Financial module by a billing and credit memo engine.

It was noted that the previously referenced Dreamforce presentation was simplified to abstract away the actual object choices, so take it with a grain of salt.

We have now replicated SFDC's internal stack for our Renewal process, and everything appears to be intelligently arranged.