Something I'd be interested to see is for you two to put your equipment side by side and take the same shot from the same distance and exact same settings and as close to the same lenses as possible i.e. both use a high quality 70-200's.
I am not so interested in seeing the same exact image, with the same lens, at the same distance. I will tell you what that will look like already, The Nikon File will look bigger.
What I want to see is the two camera go head up in a studio with the same model. Shooters have separate sessions, hearing from Andrew the MKIII falls short in the IQ department compared to the D800.
I would love to make large prints to have Image Quality reviewed by a panel of Judges. NCC would be a great venue to have the prints judged. A blind submission to see which image has the best IQ based on a print, a real world test of gear and skill.
I would think 36"x64" prints should be large enough to see close up detail. The MKIII "shadow banding" should be quite evident at that size. I have a model, a studio, and I am ready to go.
It would be fun to see what the results would be. I dont know a single person at NCC and the submissions will be unknown to the Judges, that should thwart any Nikon/Canon bias. I think It would be fun for the judges as well, two local togs putting their money where their mouth is, Canon FF vs Nikon FF. Hell bragging rights alone are well worth the effort.
What do you say Andrew? You up for putting your D800 up against my lowly shadow banding 5D MKIII in a IQ Large Print Challenge. Hell I will even pay for your Print out of my own Pocket!
So in recap, I pay for the model, I pay for the studio, I pay for the print. You just show up and shoot. You do have to upload your file directly to the printer. Then we submit the prints for Judging to NCC during their monthly meeting.
again I can kick you a few bucks. This job is for a friend so I am not charging very much. 
