You want to get a pass-through for you battery. I'm guessing you have a 510mAh?
There are, my friend has one. It does depend on the vendor that your battery came from. Some are compatible with pass-through's, some aren't unless they're specially "pass-through batteries"
This one should do the trick, there are plenty others if you look around.
eGo USB Wired Sealed Battery Charger
EDIT: I TOTALLY READ YOUR QUESTION WRONG. As far as I know, they have not made those yet. I may be wrong..your best bet is to get a 510mAh, which are cheap, for now..let me know if they do end up making/or have those. I would LOVE one.
Hope someone else can be more of a help!