Just spotted the news article about Nest Weave which will connect all Nest devices, as well as other devices using the same protocal. This includes product types such as smart locks (think August lock, Linus Yale digital lock etc) and the rest of the Nest suite.
The protocol may have been around for a while, but this is the first I've seen a company (Google/Nest) actually look to connect all of your core security and safety devices. One can monitor entry through doors, the other can capture pictures/video of people in your home, monitor temperature and Carbon Monoxide and fire risks.
I've always wanted a digital lock, but I need to wait for them to come to the UK..!
Maybe a Nest Camera in the mean time?