That's one of those cool ideas that just isn't worth it, even for a very minimal amount of power drain.
If I have this info on the unlock screen then I'm fine. If I'm already looking at the screen, how hard is it to push the home button once? I don't even have to swipe.
I've often thought it would be neat to have the external LED indicator lights on the iPhone. I get the impression this solution is comparable and quite classy. I think it would look pretty cool to have some LED lights showing right through the dark screen.