log vapes are appx 2.5 inches wide cylinder, 4.5" tall; soda can sized.
for thinking outside the box, they are also relatively innocuous looking and double as working / pass-offable aromatherapy devices, just stash the vapor tubes in the stashbox and leave the aromatherapy cup in.
not too many small vapes, at least with AC, for non AC, supreme vape might be that small (works with torch)
MFLB with power adapter as mentioned.
or if the stash fits something long, just has to be skinny? maybe a heatwand style? but then i'm guessing you can't store a bong to use it with :/