I had been holding out for a 510 Mega PCC that holds a spare battery besides the battery that's being charged. I finally found it at LiteCigUSA a few months ago. Here's a link to what looks like the same one:
Joye 510 Mega PCC.
But, I'm not sure it really is the same because it doesn't mention the extra battery slot. When I bought mine there, the description did specifically mention the extra slot. Either way, it does charge the 280mah 510 batteries. You might contact the vendor to see if it also has the spare battery spot too.
I didn't want a PCC that wasted all that space for extra cartos or cartridges since I only drip with my 510 batts. I have no need for cartridges or cartos, just the battery and atty w/drip-tip that I'm using and the battery that's being charged. Anything more is just a waste of space for me.
If this isn't the same one and you do want the spot for an extra battery, Health Cabin does carry them still:
Joyetech 510/Mega 510 PCC. But, shipping is expensive and slow unless you wait for a Health Cabin coop (which they tend to have about once a month).
I really love my 280mah 510 batteries for dripping with a 306 or 510-t atty. The original little 510 batteries are extremely irritating because they don't last long enough to bother with. But, the 280mah is fine, for a cig-a-like. It's just plain fun to use.