There's an interesting hardware software product coming from Treehouse Labs next year that is a kind of reversal on the Find my iPhone service. It's called BiKN, pronounced like "beacon," and it allows you to use small hardware tags that hook to keys, cameras, pets or even people so you can locate them.
The system also includes a special case for your iPhone that contains a receiver that interacts with the tracking tags, and of course an iOS app that makes the system complete. Up to 8 tags can be tracked at any time.
The tags have a slider that reveals a micro-USB port for quick charging. Seems like an interesting idea, and we'll certainly look at it when it ships. There's no word on price, what distance restrictions there are (I can see some privacy issues surfacing), or an exact date for availability. You can see a video of the BiKN in operation on YouTube.