Does a homemade pinhole camera count?
For you, Bob, I will say "Yes"
But look, pilots build experimental aircraft from scratch. Hardcore car guys machine car parts from scratch. Look at some of the accessories that have come from guys noodling around in a shop. Where do you think some of the things like the Promote Control came from? Or the Dynamic Perception dolly rig, controller and firmware? Or the DitoGear slider and controller?
There is no question that, the more knowledgeable a person becomes about photography, the more knowledge he is going to get about certain working elements behind his equipment. However, I maintain that there is a divergence between becoming more knowledgeable in the "geek" sense and developing skill and creativity in the artistic sense.
Not every race car driver has to become Carroll Shelby (and manufacture his own cars) ... and, by the same token, Shelby's total knowledge of automobile craftsmanship doesn't mean he couldn't be defeated by other talented drivers, who lacked his car-making abilities. Similarly, not every photographer needs to turn himself into a software geek to be able to take great photos.
In the end, it is simply absurd to believe a photographer needs the know-how to produce
a D3x himself in order to get incredible results while using one.