Oh I wouldnt bet on that. A simple firmware change could add the requirement for the proprietary battery. (All along it was speculated that Pany might eventually do this with FZ35/38.)
Also I wouldnt get too excited about an out of issue camera. It is still a small sensor camera & not the end all & be all of cameras.
In many ways what is happening reminds me of the Oly C2100. The same type desirability occurred after they were discontinued. It became a cult camera & someone was buying each & every one that came up for sale on eBay. It was believed that no camera in its class could match it. I still have my C2100, but effectivey never use it. My FZ7 is so much more preferred.
I do have to admit though, there still are some things the C2100 seems to be unbeatable in its class. Great for certain macros & that realtively larger 2MP CCD does quite well (thank you) in low lighting (hint hint Pany).