Why isn't this a thing?

I have an iPhone which I have with me almost all the time. But there's times when I don't have access to it or when it's not polite to take it out to check it so why the hell can't I bluetooth tether an iWatch (iPod nano worn as a watch) to my iPhone and receive notifications to my wrist?

I've looked everywhere online but no one has hacked something together yet and there's no rumors out there about this tech in the horizon. So as someone with no tech knowledge I, putting it out there in the hopes someone with some know how can hack this together for the greater good.

(pictured is the "I'm watch" which is the closest to what I'm talking about that I could find).