Well just get a cheap ego for the office, say the v2. That will last you all day. You get 2 batteries in a kit. 1000 mah+ will last all day, but you still have the back up if it breaks, and also something bigger, but I cannot imagine investing a large amount of money in something that "might" take. I have heard some great things about Vamo and it is reasonable, round 50ish....
Oh, maybe I wasn't very clear. The device (possibly the eGo Twist) is for me...and I'm definitely done with analogs. I'm just hoping that me getting something that he can pull longer/harder on will make him want to steal mine, and then I'll just get another. And I've thought about the regular eGo...and may end up going that direction, as I'm still pretty unclear about vv.