I am very torn between this and a D700 for ~65% of the price . I mostly shoot HS sports at my son's school. My D90 does .. ok ... I'd like the newer tech in the D800 and losing the reach from the crop sensor would be offset by the extra cropping I could do.
I would have been all over this if they were at 18-20MP with 6+ FPS without a grip.
Being an owner of a D800 I can say first hand that this is an amazing, ground-breaking, record setting camera in IQ and Resolution. That being said, if the main use of your camera is for capturing HS sports, you have to ask yourself if you would EVER take advantage of 36.3 MP. I highly doubt it. True, you can downsize your image size with the D800, but that's like buying a Porsche 911 to drive around a parking lot.
The D700 is still a top rated high quality camera. Unless you intend to print LARGE prints above 24x36 then anything more than a D700 would be wasted. I presume most of your images are for web only.
By the way...I LOVE MY D800!!!