Devices like that have existed for some time now: http://www.amazon.com/Smart-Find-Remote-Control-Locator/dp/B...

I think that there is definitely a market for both products. I can't imagine some of my ageing relatives wanting to fire up an app to find their keys (they don't own smartphones anyway), but for my use I'd like the additional features that this solution provides.

Perhaps a StickNFind base station could be built at a later stage.