Just wanted to share for those interested. I am working on implementing the Insteon Thermostat via the ISY994 platform. Currently, I have read-only visibility working, but will be working to implement controls as well. For anyone that is willing to test, the code is available on the dev branch of my fork here.
Please let me know if you find any issues, and if someone has a Z-Wave Thermostat controlled by the ISY, i’d be interested to know if it works as well.