yeah, the OP did ask for something smaller than his eGo batteries. So I'm not so sure we should have jumped strait to recommending mods. If the OP is serious about the question he or she will come back and show us that they are actually still around. But as far as something smaller than an EGo with good durability, there isn't much.
For cig-alikes, the only good options are the VOLT from smokelessimage, or the BLOOG from Bloogmaxfusion. Both of these are around the size of a cigarette but they are regulated at 3.7v so a 1.8 to 2ohm carto or atty will do pretty well on them. Although obviously, the battery life will be short and you'll need to buy a $50+ kit that includes a pocket charging case, plus 2-3 extra batteries and at least one pack of mini clearomizers or cartomizers. (and juice) So it would be an expensive investment to try something you may not even like, considering your used to the VV capabilities of the eGo spinner batteries.
If you can sacrifice size, and go with a mod, then I'd support that fully. Like others have mentioned, there are literally hundreds of mods to choose from on the open market. Some time-tested mods are the Silver Bullet or the REO or the Super-T mods, or the Provari, the BOMBSHELL (is huge and the battery will last you two or three days haha) the Legacy with a KICK, the itaste vw just came out and its a pretty small mod you might wanna look at, the MVP is a nice box mod that would fit in your pocket nicely and it does have a ring that helps protect against breaking the tank connection spot, or the telescoping Zmax, which is stainless steel. The VAMO is probably the cheapest made of the cheap VV foreign made mods. But, hey, its cheap to buy and it'll get your foot in the door. Its HUGE though. VERY long. I dont recommend you trying a mechanical mod yet because you don't have a battery tester or an ohm meter or a PV that does this, so building your own attys would be dangerous and pre-made coils can be unreliable and annoying with mechanical mods. The smoktech Natural + a KICK would be sweet too. I seriously love my Natural. I think anyone would love it. I'm going to eventually get a 2nd one. (the KICK is a vv chip you can buy separately and it'll turn any mechanical mod into a VV/VW mod) The kick would work great in a Silver Bullet as well. I have a few of the mods I've suggested and all of them are fine for pocket holding during hard labor. (I promise, mods are sturdy if you buy good ones)
WELL, that turned out to drone on way too long. Hopefully you've got some ideas though.
Please come back to this thread so we know if your even seeing these suggestions or if you've flewn the koop.