Hi Matt,
nice project

I think that your solution is a candidate to run open-source high-level frameworks, like Freedomotic or openHAB.
I'm working on open-source home automation since last year with the Souliss project. Is a home automation framework that run over AVR, that cover:
- Communication between nodes,
- Node interaction and home automation logics,
- User interfaces.
We may found some common interest in the collaboration, Souliss is distributed and let control directly the devices in the home, but for some activities a central hub it could be helpful. This is why we are working on the integration via Modbus with Freedomotic and openHAB, to provide a central point of control out of the integrated user interfaces available in Souliss (that for now is an Android one).
You can found some more details on the weblink in my signature.
Regards,
Dario.