Very interesting approach and a well written article! I've been looking for scalable and redundant SSRS farm alternatives using Standard Edition to save on licensing costs vs. Enterprise Edition.
What would be the solution for Report Subscriptions in this scenario? Since the Subscription details are written to the local ReportServer DB, there would be unique Subscriptions in each container, so I wouldn't think the image would be reusable in that case.
Thanks again for the great write-up!