Openfiler is an operating system that provides file-based network-attached storage and block-based Storage area network. It was created by Xinit Systems, and is based on the rPath Linux distribution. It is free software licensed under the GNU General Public License version 2. Its software stack interfaces with open source third-party software. http://en.wikipedia.org/wiki/Openfiler
I'd love to be able to run Tonido on my Openfiler box. This seems like a perfect fit. Openfiler shares files locally, Tonido can expose them externally.