The pill fob is great, I've been thinking of those and portable ashtrays for a mod body. also, another way to go with this (if nothing else conceptually, you've already got a working model) take a dead atty, gut it except for the tube and connector to the battery, and then put a battery connector on the other end, much like you've got. I'm thinking in terms of 501's and I think you have 901's??
What you're basically talking about here is the "charging extender" that we use to run the eGo/Tornado batteries off of a standard (slow) charger. It is an atty-length piece of tubing with an atty connector on one end and a battery connector (510) on the other. You can get them for a few bucks each.
That is exactly the unit that I used when I was building the TorneGo I prototypes. Holds about 1ml.