"Maybe it would be easier to make suggestions if you describe what is wrong about your D700 that you want to correct with a new camera".
There is nothing wrong with my D700. I am very fond of it. It is just that I want top-notch quality 20 x 30 inch landscape images and the D800 could give me that with minimal interpolation.
As to the question of downsizing, what I had meant was that I do not want to compare the digital noise after reducing the resolution of the D800. Maybe you could educate me further on this. I often read that if you downsize the image from a high-resolution camera and then compare the digital noise to another lower resolution model, you may not find much difference and so on and so forth. My way of thinking is that (and may be this is where I am wrong and you are right), it seems odd to have a high resolution camera and then reduce the resolution when it comes to comparing the noise. When we compare the image quality, we compare it at full resolution (for example, we say that image quality from a D800 is superior to that from a D700; at that time we do not say that we are comparing the D800's image quality at 12MP resolution to a D700, which is also 12MP). I hope you have understood my logic (right or wrong) and would be very pleased to hear from you.