Sarah, I have 5-10 good reasons why you should just hang on to that e-Power for the moment, which I'll give to you right after you look at these pictures to get some better perspective on the size of the 14650 is relative to devices that aren't as dinky as your Greensmokes thing.
This picture shows the Joyetech eGo 1000mah battery (it happens to be a passthrough [USB port on bottom]) next to the Smoktech e-Power 14650 (on the right), with a ballpoint pen on the left for scale.
And here is a pic of the E-Power 14650 with a chrome eGo Mega Dual Coil Cartomizer (EMDCC) on it, which it looks like it was made for:
Now here's a pic of the Joyetech eGo, probably about the same exact size as your proposed kGo, with a Smoktech 3.5ml (DCT)tank on it:
And lastly is a pic of the Smoktech e-Power 14650 with the same tank on it:
So this is the size difference we're really talking about. Not that dramatic, is it?
I'll start with that on my "Top Ten Reasons that Sarah should hang onto her Smoktech e-power 14650 for the time being":
10) The size difference likely only seems dramatic compared to the dinky little thing you're used to
9) Fits EMDCC like a glove
8) Looks good with DCT tank as well
7) Replaceable batteries - easy to upgrade batteries, can be charged without tying up power unit
6) Replaceable switch - keeps long term costs down, husband off your case
5) Only cost you like $45, and can be sold to friend dying from smoking if you still don't like it after trying it
4) You can buy a multiple battery charger (cheap) so you'll always have lots of fresh ones on hand at all times
3) Sending it back is a hassle for you and the vendor
2) You can experiment with different battery types - high drain, regular drain, different chemistrys
1) It's probably just right for your husband, who will almost undoubtedly be wanting a PV
So that's it. Please don't send it back.
I've bought four them so far for friends who are killing themselves, and am buying about four more this week. Surely there's someone you know who needs to stop smoking, and what better way to start them out than to hand them a setup of their own and say "here, use this. If you like it, you can buy it off me." If you don't keep it around for yourself, please consider hanging on to it so you can help someone else. I'm at around six people and counting whom I've gotten off of cigarettes, and that's in the last three weeks. It feels good saving someone's health, if not their very life; try it, I bet you'll like it.