I had an Olicamp Space Saver Cup ( https://olicamp.com/space-saver-cup.html ), famous for nesting conveniently with a 1 qt. Nalgene bottle, and I wondered if there was a stove to go along with it in order to make a complete kit similar to the military canteen-cup kits.

Well, there is:
G.A.K New Stainless Steel Bottle Backpacking Stove
https://www.amazon.com/Stainless-Steel-Bottle-Backpacking-Stove/dp/B077JMH8BD

The stove nests over the Olicamp cup, to make a nice, compact kit. Because it's all stainless steel, it's probably heavier than a backpacker would want, but it sure is sturdy! (For those willing to make the ruggedness / weight / cost tradeoff, there are also aluminum and titanium versions of the space saver cup.)

As suggested by one of the Amazon reviewers, I made a slight modification to the stove to improve use with a Trangia burner (creating a gap between the top of the stove and the pot). Outside, with a slight breeze, I got 16 oz. of boiling water in about 9 minutes.

I put up pictures and more details here: https://7402.org/blog/2021/olicamp-cup-with-stove.html

I'm interested in seeing if it would work at all with a Sterno can. The internet consensus seems to be that Sterno is a pretty miserable fuel for this kind of use, but the appeal is for long-term storage, especially in the trunk of a car. Maybe it would take twice as long to get boiling water, but it would more convenient and/or safer for storage.

I prefer Esbit tabs to Sterno for a durable, storage capable fuel source. Even better is a canister stove, which will easily boil water in something like three minutes or so. There are all sorts of burners available for canisters but I stick with my old faithful Pocket Rocket. it does need a wind screen occasionally, which is easily improvised.

I usually have Esbit tabs packed away in my kit. There are times when they are just what you want.

Another possibility is this: https://www.rei.com/product/129634/vargo-triad-multi-fuel-stove.

The Vargo titanium stove. I have one but haven't used it much - extremely light - uses both alcohol and Esbit

For what it's worth, I did try the stove with a can of Sterno (2.6 oz size, Ethanol gel).

After 20 minutes, there were definitely some bubbles at the bottom of the cup, but it would be a stretch to call it "boiling." At best, the water was maybe hot enough to make tea or coffee.

So I can confirm that Sterno is not a good choice for an emergency stove of the simple stand type.

I would suggest some sort of alcohol burner. A wide variety of fuel types are available, including high proof booze. I have actually used Purell hand sanitizer (60% alcohol) with success, although expensive. Premium would be Everclear, usable as a disinfectant and stove fuel, as well as drinkable.....

Digressing slightly into solid fuel stoves. The British Army is experimenting with a new one for the crusader cook kit, called the FlexiStove.

It's not made from sheet metal, but some layered stitched together material. Packs flat, and when pull it open forms like a shelf for the tab to sit on. And the whole crusader mug drops down into it, effectively making a windshield.

One advantage seems to be it doesn't hold heat for long, so can pack it away soon after use.

That's the one.

Be interesting to see how it holds up once gets into more hands.
Bit sceptical of the 400ml boiling in 4 minutes claim though.

While looking into the FlexiStove, I came across this current stove from the UK:

Bushcraft FireDragon Multi-Fuel Cooker
https://www.amazon.com/dp/B01CJZWBPK

and this fuel:

BCB Adventure Fire Dragon Solid Fuel (6 x 27gm Tablets)
https://www.amazon.com/dp/B00R33ZI0Y

The fuel looks especially interesting as an alcohol-based replacement for Esbit tablets. It is more expensive (about $1.50 apiece), but that might be OK for occasional or emergency use.

The reviewers on Amazon seem to love it. Here's one that's typical: "These gel fuel tabs are awesome. Burn hotter, better as well as cleaner then the older trioxane, and hexamine tabs. Doesn't leave that heavy residue on my mess tins. Doesn't smell so toxic like the other fuels either."

Anyone here have first-knowledge about these?

Certainly more pleasant to use than hexamine.

One common gripe is that maybe the tabs should be little larger, one can struggle to get 500ml of water to fully boil.