While some people may be sitting back and waiting for the devices to start rolling in that have the kill switch technology built right into them, there are already ways one could do similar types of functions that a kill switch would provide. One way in particular is the Android Device Manager app from Google, and it just recently received a very handy little update that comes along with at least one new feature. Android device manager was one of the more useful applications to have on your phone before today's update, allowing users to locate a lost device from the last known location since the gps pinged a server, and also allowing the user to ring the device if it may be lost in your immediate location around the house, lock it, or wipe the data with a reset should you fear it is lost forever.
This was only really useful though if you lose a device and have another one to use to log into, or are near a PC that would allow you to access the web. Well, no longer! Google has updated the Android device manager app with a brand new way to locate and wipe or ring lost devices. By way of a guest sign-in through another users Android device manager application. Yes, users can now log in to a friend or family members Android device manager app and sign in as guest to access the same functions they could if they were logging in on their own device. Lock, ring, and erase features are all there so you get full functionality of the app even in guest mode through someone else's app.
Android device manager may not always be a usable solution for you, but if it is at least now you can rest a little easier that if you lose your device while you're out and about with someone else, so long as they have this app you can attempt to find your device again or take the necessary steps to secure any personal information by locking or erasing it from existence. The app update should already be rolling out to devices now but it may take some time for it to hit all devices.