I'll go with the Gripper personally, cheap and small
This mod gripped my attention.
The pocket-size ecigs I have are not pocket-size enough. The smallest one I have is an Ego 650mah. Attaching a carto and a drip tip adds to the length, which is not exactly safe and comfortable in the pocket. So it's not really the width or fatness that's causing the problem. It's the unnecessary length. I also have a 2AA box mod and have been trying to find time to modify it and come up with one that puts the connector all the way inside the box.
Anyways, such config like the Gripper in the photo is the only design you can come up with to solve the length issue.
I might have one of these Grippers someday. I've read some issues about them like connector inaccessibility, etc. But it's definitely something that manufacturers should consider adding to their future products.
One obvious modification would be to just add some kind of a clamp, instead of a continuous tube housing the carto, which would expose the connector for accessibility.
I laud design efforts such as this, nonetheless.