I just bought a D100 here in Japan and the colors seem fine out of the box on Auto White Balance.
Before buying it I had read about the problems with exposure, etc. here on Nikonians and asked the camera shop about it. They said that Nikon has made adjustments and they sell about 5 a month and no problems. I imagine that the D100s here in Japan are the newest out of the factory.
You might want to find a shop that sells a lot of D100s, ensuring you get one from the freshest batch, even if it is $100 more than the cheaper outfits.
This is my wife, all settings are auto except the white balance is Cloudy -3