6MP is more than enough for a small print of 20" wide.
I guess everyone has a subjective definition on what is "good enough". It certainly cannot compare to film. I found the D40 was lacking for prints bigger than letter size. 6mp printed to 20x17's lowers the pixel density quite a bit.
The word stunning means professional level, no loss of detail, etc. You could print a 20x17 with a 1MP cameraphone, but that doesn't mean it'll look great, unless you look at it from 60feet away.
It is very worth nothing that the 16mp of the D7000 is only a modest improvement in resolution over the D40's 6mp, even though in mp it sounds huge.
If you do the math, if you need double the res, you need to quadruple the resolution. So double the resolution means 24mp is needed. Thom Hogan writes a good article explaining max print size.
While the D7000 is not able to print 'film' like quality, I am looking forward to better 20" prints than what I did with my old D40.
The more and more I use the camera, the more I love it!