With the local SDK, static files have a special handler which can serve their data without requiring the instance to be executing.
It strikes me that it would be useful to allow for a redirect handler as well. This would help for static files where you want to store the files in a Google Storage Bucket so they can be updated without requiring a deployment of a new version of the app code, as such I've submitted a feature request for this in 10459.
By extension, it would also be useful to allow for a redirect handler to google storage either dynamically or only if a GS object exists in order to support caching. IE a PHP application could dynamically generate HTML for a page, then save the html to Google Storage under a pre-determined object name and in the future the redirect handler can access that instead:
Don't know if others would also like this, so I figured I'd post about the requests here in case there is broader support.