I really like to have a cup/pot available in my minimal outfit so that I can provide hot liquids and met snow, etc. if necessary. I usually do this with a cup fitted on my canteen - I come from an area where at least one canteen is essential for all but the most trivial excursions, so the cup is a good solution.

Nothing even close to being a decent cup will ever fit neatly into your pocket, even a cargo pocket, if you are going to do appreciable walking.

There are all sort of non metallic folding containers that can hold water but that can't be placed over a stove or flame. Just thinking out loud, has anyone ever tried stone boiling to achieve hot water with a container of this sort?

I think I see a project unfolding....