I'd like to build my own layer on top of a public [Docker](http://www.docker.io/) image. Fine, I know how to do that. However, my layer will contain proprietary code that I can't share in a public docker image. I do, however want to be able to share it among servers inside my organization.

Is my only option to run my own instance of [docker registry](https://github.com/dotcloud/docker-registry)? Or are there workflows that allow moving of layers/images around without a central repository?