It is possible to show devices and some devices do have the ability select the capability to show on the tile. But this is based on the device class and only for system capabilities.
It would be really great if we could have a system widget where we can select a devices capability to be shown directly upon the dashboard. (Kinda how you are doing for showing a devices snapshot capability)
This would then allow point in time dashboards of the current state.
As well as to display two pieces of information aka tiles on a specific device. (Ie dashboard for motion alarm and temperature)