It was actually me that abbreviated Pio/Kuro (thanks zildjian), but I'm surprised it wasn't clear.
That said, you CAN still find Pio plasmas. However, not the 6020s, but the much more expensive 141/151/111. Think $6000 and up. They're still quite available, at least through CI avenues.
AVRat is correct, the VT25 is the most desirable of plasmas currently made. The V10 and S1 were superceded quite a while ago.
I still stand by my thought that burn in is a myth (outside of the extremely off chance that one is actually considering a demo model from BB of all places), but what you MAY suffer sometimes is IR (image retention), depending on how cranked up your settings are and/or how long your image is up for. It "washes" itself out, however.
My brother has done plenty of gaming on a Pana plasma, never had any issue, even with say a "map" in the corner for a FPS, however, there was some game that did incur IR, and he got worried. I explained what it was, specifically that it's not burn in, and he hasn't made any mention of it since, and has been gaming with happy abandon since.