I've been looking at the BT/WiFi battery powered chips that attaches to items you want to keep track of... currently marketed for finding keys, wallets, and cell phones.
The concept usually involves downloading an app that can communicate with the chips and locate your own. One brand is featuring an app that reports the location of every chip it discovers (apparently to the cloud servers). I think the idea involves using the cloud so that a chip can be discovered (eventually) anywhere in the world.
This type of device.... could be a fascinating thief prevention tool if the apps and chip technology was to become standardized.