Risking the wrath of D700 owners i watch the secondhand sales at a company called Wex and although lcd clouding is mentioned for different cameras there is a tendency for it to be D700s.so long as its usable i dont see it as a problem though i guess it could get worse over time.
Just had a look on the WEX site they have 7 D700s for sale with only one mention of clouding and one of fogging dont know the difference,so at the moment its two out of seven.It could be that this is the only company that will take them in as a trade in with this problem so it would then make it appear more common.
That replacement cost isnt bad if you buy at the right price.