for what it is worth to readers of this thread,
I have the p65v10 (I think an August 2009 build).
I have about 600+ hours on it.
I do not have any of the issues that have been reported in this thread (at least not yet).
No visible change in black levels.
Watching hd cable looks great.
Watching bluray looks great.
I read somewhere on this forum that reading posts here at avs
(with all of the potential issues people may encounter due to a defective panel or a design defect; small number of incidents per issue, or many incidents per issue)
will make one unable to enjoy watching a tv again...
It was meant as a joke (or so I think???), but they were right
So, unfortunately for me, I am always on the lookout for IR, dead pixels, fading black-levels, buzzing, etc. - I would see issues if they were there; nothing (yet).
To gain some perspective on the issue(s), it would be great if someone could create a 'poll' thread for this issue (if not done already). For example, sample questions could be: do you have the issue or not, year and maybe month of build, size of panel, hours on panel, % level of black-level change, etc.
Might help identify a pattern.
Might help people who are considering buying a 2009 panny plasma.
It also might help people with issues who can then go to panny with #s to backup their claims (in force).
Best of luck to those who have had issues; I hope you can get things worked out.