FWICT, storage limits are still not directly supported.
You can however create a user per container and limit that user's quota.
This is the relevant user comment (but the full discussion is insightful): https://github.com/dotcloud/docker/issues/471#issuecomment-2...
I'd be interested in this as well. The workarounds mentioned seems to require a bit to much hacking for my liking.
Are there any actual plans for implementing simple disk-usage (and perhaps network) limiting?