@davglass made a Proof of Concept smartapp using iBeacon detection to flip a SmartThings switch. It does require a $25-$33 iBeacon, the $9 Beecon+ app, and an iOS device. And it may use a lot of phone battery depending on exactly how you set things up.
But it’s working very well for me for microlocation, much more reliably than either just the phone or the ST fob. Mine sets off every time about 10 feet from my front door.