I think I spoke too soon....
491 hours in on my 54G10 and my black levels have increased noticeably. It happened last night.
In all honesty, It doesn't really affect my viewing when I'm playing games, but when there are dark scenes in a movie, I feel like there is a dramatic difference from the extremely dark blacks before the change.
Before the change viewing a completely black screen at night with all the lights off almost made it look like the tv was off, now it's distinctly gray.
I don't know what the hell happened to cause it to just change like that.
It bothers me more because I've been visiting these forums and I know the issue exists. Perhaps if I didn't, I could be blissful in my ignorance.
I can still return/exchange it at Sears, but I don't know if I really want to. Yes, the black levels have increased, but the picture still looks great, especially in games. I can notice the difference in movies but I'm hoping I'll just get used to it.
From what I've read, it seems like Panasonic has no intention of fixing the problem. I'm going to give them a call tomorrow and see what they say.