Where Is My Head-Tracking-But-Not-Really iPhone App?

I’ve asked for this before, and I honestly expected somebody to have built it by now. Everyone remembers Johnny Lee’s rockstar Wiimote mod right? But instead of moving your head, you’d be tilting your iPhone left/right/up/down to achieve the same effect.

Imagine the mockup below, but instead of my kitchen, you’d be fighting wave after wave of zombie aliens. Seriously, why isn’t this built yet?

iphone-look-leftiphone-look-right

Somebody please make this happen, and you will surely reap untold fame and fortune.