Well, like YKruss said (well, pointed to), the MV stuff will let you build your own. Now, that may not be what you are after, but you may wish to seriously consider it if you don't mind soldering (or learning to). Now, if the Zombie Apocalypse occurs, you're going to want to be able to assemble stuff into a PV.....
I use mods, and am currently using 2 types
1) The 3.7 volt types like the 510 Box
mod Kit above, and
2) a 5 v passthrough (a direct PT).
using
6 Foot USB Extension Cable
2 amp AC to USB Adapter, ideal for Passthroughs
and parts for the usb PT e-cig.
There are tons of links in the modder's section that will help.
Modders Forum
Now, the 3.6/3.7 volt box mods are using inexpensive 14500 900 mah protected batteries at about $5.00 each. Combined with a dual charger and I can vape cheap, or have a fall back plan for anything. You can also get a kit:
Blue Lightning DIY Acrylic Tube mod Kit - currently out of stock. I have one, it's nice.
Now, 5 volt box mods just use 2 3.x volt batteries and some form of voltage regulator/power regulator. See the modder's section. Maybe a 3x AA size box with connector/button/electronics in the center..........
If you're looking for a pre-build mod, you already know about them, since you are using a buzz.