I read some comments that Panny bought Pioneer plasma tech and rolled some of it into the "V" series. Not sure how much truth there is to that.
Panasonic bought the tech when Pioneer vacated the biz a few years ago. I know that the tech hadn't really been used through the 2010 model year, though. My only guess is that production cost must be a determining factor. Those Pioneers are/were amazing, but there's not much of a market for a $3000-$5000 plasma tv, when 98% of the population could spend $800-$1200 for the same size Samsung or LG and not notice the difference or care.
My guess is when tech costs come down enough, Panasonic will probably introduce it into their premium line. If they were smart, they would have purchased the Kuro name,too. Then they could distinguish the premium class from the consumer grade stuff, i.e. Panasonic Kuro or Viera-Kuro series. I've only ever seen one Pioneer at a store once, but even I would pony up some extra cash just for the name on reputation alone if I believed it had the same DNA.