2 things:
 - `instance_request` has nothing to do with the url being namespaced, that is taken care of entirely by the url patterns.  All `instance_request` does is take the `instance_url_name` parameter to the view and query the DB to replace it with the `instance`, which you are then not using.
 - You will *have* to make this not be on an instance url if you want to use it for instance creation.  After all, if no instances have been made yet, what `instance_url_name` will you use?