I've not seen a single picture of a device that actually has backlight bleeding. Not one. What I HAVE seen are dozens of people claiming their device has backlight bleed because they don't have a clue how a backlit LCD screen is supposed to look...i. e. blacks are a dark grey, and NOT the true black seen on an AMOLED screen. My guess is that part of this is due to the large number of GNex and SGS3 users that have picked up this tablet..they are used to seeing AMOLED everyday. They see the screen is lighter on a black background (and maybe slightly more so over the LED backlights themselves), and they think the device is defective. It isn't. Or the vast majority aren't. That's why it was never spotted by the dozens, maybe even hundreds, of professional reviews that look at tech for a living.
If your device has backlight bleeding issues, please post pics. I've had four N7's pass through my hands, and not one has had the slightest issue in this regard. Since you claim to have had 10 defective devices, I'd assume you have pics of at least one problem of this kind.