Would you pay extra for ultimate QC?

I would disagree with you here...... People pay a premium for a product because they expect a high quality. This is the reason I see for the high price of the D4. It is built like a tank.

Its why someone would pay big bucks for a Zeiss or a Leica lens. They are generally built like the proverbial brick house and made sure it leaves the factory operating as it should. The tactile feel etc etc are all regarded as top notch.

I don't here much complain about QC from these makers. Its usually I like it or I don't like it, not I got a bad copy. You pay for it. In contrast, the Tamron 17 - 50 2.8 is regarded as an optically brilliant lens. What do you hear?  It is brilliant IF you get a good copy, There are focus issues, Optically better than the Nikon or Sigma, but..........

Sometimes there is a need to realize that the high cost of certain goods are because of the extra level of quality control and manufacturing quality. We all pay for quality control, but there are different levels of it. I don't think the quality control on the 24 - 85 is the same as the 70 - 200 VRII or even the f4 version. I have the the 24 - 85 and the 70 - 200 f4 and the build quality is just extremely different. The zoom ring on the 24 - 85 feels stiff and jerky in comparison, I have to play with for a few seconds for it to feel decent. It FEELS cheap. The 70 - 200 f4 FEELS better built. The difference in price shows this. Better manufacturing, I believe, from the same company. This is one of the reasons for the price premium in my view.

You will get a dud now and then, but if it cost me a few bucks more to get a higher level of both manufacturing and QC, Then I will pay for it.

Just so you know I just recently bought a D600 that has a dirty sensor. Other than that, I am stoked. The camera is solid and is a definite upgrade build wise over my D90 and D5100. If it cost me $200 - $300 more for no oil or sensor dust, then I would have paid it.