After a couple of weeks of me running it myself, I've now made a Node-RED module public. Available on NPM/Github: https://www.npmjs.com/package/node-red- ... -tellstick. With this module, you may receive and transmit data from/to the Tellstick.
Node-RED is a fantastic tool for wiring together hardware devices, APIs and online services in new and interesting ways. Here's a screenshot of how it may look:

Here's a small video of me controlling my bedroom lights via Node-RED on my Raspberry: https://www.youtube.com/watch?v=qWhjNiy9fuU.
Feedback is always welcome!