Looks like only the older version had the 9V/12V out.
I actually wasn't joking, but I also wasn't suggesting you get that exact model. It just seems difficult to find pocket-sized battery packs with enough voltage (as most are designed to recharge phones/tablets).
Went through the same thing; I feel your pain. My Pax stopped heating up (the heating coil/circuit got fried somehow), and I purchased it on ebay in December 2012. Unfortunately, once you've given them the serial number, you're fucked.
I ended up buying another one because I missed it so much...
If you've given them the serial number on your Pax, you're out of luck as far as warranty options go. I made that mistake when I didn't know Ploom doesn't cover units purchased on ebay.