Actually. . . .
Micro chipping is common and a requirement in certain states (Florida mainly comes to mind). But this is only good if the snake is found and scanned - like that of a dog chip, etc (AVID Chips)
There is no GPS tracking mechanism that will be usable at a consumer level, but you can get Radio Frequency transmitters that have batteries that last years and years, simply because they are just emitting a low frequency that can be picked up with a wand and receiver. These telemetry tracking systems are used in animals in the wild that need to be captured and recaptured. It is not a cheap system, but it is an option for some folks. It has to be surgically implanted, and is the size of roughly a AAA battery. But it does not get passed through their system, does not come off in shed, but of course is not traceable via any method other than radio telemetry.
http://www.lotek.com/nanotag.htm here is some of the new tech that is available in radio telemetry but this type of equipment is more geared toward researchers, not pet owners. Though, it could be used by both all the same.