We have no plans to add a smoke detector to our product range at this time. However, this is something we may consider in the future. The Motion Sensors have an environment check built into them so they will detect a change in temperature where they are located.
In addition, the Boundary system allows the use of IFTTT and Smartthings to provide communication between other smart home devices so it’s certainly possible to extend the Boundary system to work with other products.