m sorry Liquid Turbo, but I have a close friend who took a picture with a D1X which ended up being printed onto a billboard. Now that camera is less than 4 megapixels and substantially noiser than a D40, and a billboard is substantially larger than a 20" print. So I believe that any camera can print images of any size.
Fact of the matter is, when an image is larger, you look at it from further away, so the image quality you need for a large print doesnt need to be any better. So a 'stunning' print of a large size should be judged from what you call "far-ish"
A billboard is viewed from many many feet away.
My point was if you make a 20" print and turn it into a book (such as I did), there simply isn't enough detail in the D40's 6.0mp to make it a stunning. It can't be compared to a D3x's 24mp making the exact same shot turning into a 20" print.
My 20" prints with the D40 all look great when viewed approx 6 feet way. When viewed up close like a book the shots could not ever be used professionally. (Quality-wise, not composition-wise)
It was actually one the main driving reasons to upgrade to the D7000. The D40's great for making prints 8.5x11 or smaller. It's absolutely brilliant for printing regular photos..