FIX FOR REAR CAMERA AND FLASHLIGHT!!!
I also had the same flash and rear camera problems as everyone else but I figured it was a software problem.
To fix the flash/flashlight, simply download the flashlight app. The one everyone used before iOS 7. The flash should work immediately.
To fix the rear camera go to Settings > General > Restrictions. Enable restrictions and turn the Camera off, then take the restriction off. Check your camera, it should work immediately.
Hope this answers a lot of questions and saves a bunch of money due to Apple's failures.