Sure! It’s not perfect by any means, but I created a custom object called “Product Subscriptions” and added the field attributes that you mentioned above. I also created a workflow that will create a future renewal when a deal is closed as won. In that same workflow, it looks at the product lines set up on my deal to create a “subscrtiption” record, and copies the quantity, start and end dates, and price from the line items on the closed won deal as property values on the subscription record.