He was including the 1.7 teleconverter in the formula.
Comparing apples to apples, the 80-400 has an equivalent reach of 600 mm with the crop factor, is one pound lighter, 3" shorter, and approx $600 less expensive, new.
Your question is a tough one, as both lenses are excellent. I have had the 80-400 VR since 2004 and it is my workhorse. I do sports action photography and need the reach of a 400mm lens. I have also had the 70-200 lens and it is the better of the 2 out to 200mm since it is a faster lens and also has faster focusing ability. I use a D-700 now, but used both also on my D-100 and D-300. For your application, I would have to recommend the 80-400 VR, since with the D-7000 you have the advantage of the crop factor, it is a more compact lens, and focus speed is less critical than with sports action. I used to shoot handheld with the VR function on, but now I use a tripod with the VR off as much as possible, as I get a higher percentage of great crisp shots.
You should check out Aberdeen for the boat people, in Hong Kong. In BKK, there are some really great opportunities for street photography, so have your camera ready. I missed a shot of a guy riding an elephant down the street since I left my camera in the hotel while I was working. I would also see if there is a kickboxing demonstration at one of the hotels, like the Oriental. You really don't have to go far to look for photo ops there...
I have used both the expodisk and grey card with my Nikon D-700, and get the same great results, both better than Auto. I take a lot of sports action and always have the expodisk with me, as it is very quick, and easy to use.
Lots of conversation and complements
I also used Opanda prior to purchasing a D-700. It works well.
There is nothing wrong with the SB-800. It is by no means obsolete, as it can functionally do anything the SB-900 can do. The SB-900 is a bit larger and has more light output at the upper end, but has no additional capabilities over the SB-800. Alot of photographers actually prefer the 800 as some have had issues with the 900 overheating with fast repetitive use. I have heard many times that you should date the body and marry the lens. This is very true. Build up your arsenal of great glass, like the 24-70 f2.8 or the 70-200 vr 2.8. You can't go wrong and this glass will not be obsolete anytime soon...
With the lenses you have (all FX), the decision is a very easy one. The D-700 is an outstanding camera. I have had a D-100 (DX) and D-300 (DX) and now own a D-700 (FX), and am completely sold!!! When other people are putting away their cameras due to low light, I am able to turn up the ISO higher than any of the DX camera's I owned and not have an issue with noise until I get to the extreme. I also like the extra flexibility to crop the photo in post production that the FX format gives and the benefit of a wider field of view (wide angle lenses are truly wide). Since this would be a second camera body, you still get the DX telephoto benefit, so you have the best of both worlds...
Looking at the type of photography you do, I would strongly recommend getting a DX format camera for your second body. The d-700 is a great body for Theatre (low light, high ISO), and candids of children at play (full frame), however, for the sports photography, you need more reach than the 70-300 lens will give. The DX format will give you the reach without having to buy a longer lens. The D-300 is a great recommendation since it uses the same battery as another person suggested, but is also uses the same storage device, and the price has come way down. The D-300S would be more expensive, but would give you the addition of video.