Your enquiry concerning zooms for wild life photos is highly welcome...but in your tests or future tests no 400mm, 600mm, 800mm Nikon...
Most amateur photographs are looking for wildlife zooms at a good second hand price: 1500 - 2500 euros
Ken Rockwell on his site suggest to use a 400mm AF I F2,8 and a TC 14 E teleconverter: this is the kind of equipment you should test for people who can't afford a brand new nikon lens...
There is a big potential market there, and also, a company like yours, could offer a test bench where we could get a test of a second-hand lens, at a fair price, so as to see if its worth buying it...
The potential sellers and buyers could then do the deal in total confidence, or publish in their selling advertisement the test you had done for them. (Cost of test should be around 100 to 150 euros)...
Regards