You can view all sorts of lanterns at the batteryjunction site. They have two flashlights that you pull to make into a lantern, called the Wagan Brite-Nite Pop-Up and the Nite Ize 3-in-1. Oh, and the Nitecore LA10 is super small; I guess it can be used as a very diffuse-flood flashlight in addition to serving as a lantern.
For compact (strictly) lanterns, also have a look at Princeton Tec Helix, Streamlight Siege AA (I have the larger Siege for D cells and I like it), and the Brite-Nite Dome.
(edit) Oops, I forgot you wanted something that runs on 18650. Well, the site has some of those, too. Nitecore LR12 might be worth a look.
I bought one of those single 18650 light/lanterns years ago, and modded it to a three-way light for backpacking. its a flashlight, pulls out to be a table lantern, or the end/sleeve removes so its a hanging light. (i can take some photos or do a quick video of it.
I don’t know if it’s still available but Solarforce made a pretty good lantern head assembly and tripod stand that fit all of their 18650 sized flashlights that had P60 drop-ins. One has been in my kitchen since about 2012.
I was considering this Solarforce lantern head, it looks pretty good. I’d love to have something very small, something 21700 battery size, maybe rechargable, with high CRI, and it’d be great to have it like DBSAR mentioned, convertable to standard flashlight…
Couldn’t you take almost any tail standing 18650 and put a diffuser on it? And if you want to restrict upward pathway of light, just take a wide plastic lid & either affix with poster tac or cut a small hole to seat it over the top of the diffuser. And, for hanging, just use an 18650 with magnetic tail cap and attach to metal fixture above.
What about designing a head similar to the Solarforce lantern head but with an average diameter compared to the most popular flashlights. It would then need a selection of adapter collars that enable this to thread on to a range of those lights. Pretty much a universal lantern head with adapters. Probably not as desirable or efficient as a purpose made one but certain useful if you have nothing else?
I’ve got an LT1 on its way and already use the Solarforce lantern head, it does the job and you have the ability to put any type of p60 light engine underneath it for whatever tint or lumens or battery config you want.
For some reason I don’t like adapter, I have a Fenix lantern adapter and a few aftermarkets. Don’t like the idea of forgetting to bring it or misplace it.