You asked for 100-150w range... a single 18650 cell battery mod will never go above 75w no matter what manufacturers or anyone else claims unless it comes with a built in lipo which I would never recommend. That puts you in dual battery mod territory, the smallest I know of are either the joyetech Cuboid or the istick 100w, out of the two I like the Cuboid more and I believe it's also a tad smaller.
joyetech Cuboid
iStick 100w
Good luck with whatever you pick.
joyetech Cuboid

iStick 100w

Good luck with whatever you pick.