Stan, have you tried the focus chart on your camera? My guess is that if you do it will show a degree of back-focus. probably not enough for you to have noticed in your photos', the same as I didn't notice on mine, but it's there nonetheless. Why don't we assume that anyone who feels the need to return his equipment as faulty, sees sufficient out-of-focus (more than is able to be adjusted out in the AF Tune) and in more than one body, is given the element of doubt. *
I think my suggestion that since March 2012 the Thailand factory has been re-equiped and may be producing some cameras (the D7000 if not others) that have an excessive AF offset due to mis-calibration for some reason, is a reasonable one.
* In Internet slang, a troll is "someone who posts inflammatory, extraneous, or off-topic messages in an online community".