1) The crop factor of the D7000 and the 36mp of the D800 is a wash. 2) You would probably want to acquire a 16-35 or other wide angle. 3) I'm confused. Having been discussing a move to FX with the loss of the DX crop factor, your Plan B is to stay with DX and go for longer glass???
What do you like to shoot, and what current lenses to you use the most? That analysis may guide your equipment decision.
BTW, if you opt for a TC, skip the 1.7 and go for the 2.0 III.
Jon Kandel A New York City Nikonian and Team Member Please visit my website and critique the images!