I don´t think that UV2A Panels are used. They are very new panels. Even Sharp, the developer use this panels first in the new top series. I think Sony use normal Samsung and Sharp Panels, dipending on the size and line.
But for me the PQ is important, not the type of the panel. The first rumours says that the UV2A panels are not so good everyone hopes. Only evolution no revolution. And Sonys Bravia Engine is one of the best, so i hope the PQ is good for me.