There was no communication from Nikon, but out of the blue my D800 was returned today. It's in good clean condition and the LCD matches my Colormunki Display calibrated monitor!
From the enclosed impersonal letter, you can see that they have dealt with this green LCD issue before and they already had a fix in place. I really wonder why this couldn't have been done with a firmware update.
Back in April Nikon claimed that the greenish D4/D800 LCD screen is more accurate than the D3s/D700 and never publicly acknowledge this as an existing problem.