At the State of the Union we introduced that we're working on a new Z-Wave integration. It's based on a new project by the Open Z-Wave project called OZWDaemon and we will communicate with it over MQTT.
This new approach allows us to integrate directly with the core of Open Z-Wave without relying on bindings via other languages. This allows us to easily keep up to date with the latest Open Z-Wave versions.
There has been some great progress on the integration thanks to @cgarwood and @marcelveldt and you can start testing it out today as a custom component. It's still early and not every device type is supported yet. Currently it supports lights, switches, sensors and binary sensors. The custom component is powered by the new python-openzwave-mqtt package.
Please try it out. If you find any bugs, create an issue. If you are using Home Assistant 0.105, use the new mqtt.dump service on topic openzwave/# to make a dump of your Open Z-Wave instance and attach that to your issue. The dump will be written to mqtt_dump.txt in your config folder.
Once the integration is mature enough, it will become part of Home Assistant Core.