If your usage is with baseboard heating only (120/240V), the only thermostat out-there that can be remotely controlled for that usage is the following:
This is a new device in pre-order now. They are supposed to publish their APIs in 2015. As soon as their APIs are published, I can work on integrating it to ST just like I did with the ecobee thermostat.
See the following links about the work I’ve done for the ecobee thermostat.