have you thought of a wide-mouth stainless-steel bottle for that purpose?! together with an attachment to hang it over a fire it should meet your requirements.... (it would make also a solution for a PSK container-together with a small bag to store contents when using bottle)
i always carry a whistle and small stainless-steel mirror on my dogtag (learned from an experience on restoration island in 2007...)and a neck knife+ some form of firemaking device in my pocket. should i go out of the place where i work/stay (=rather large property) i carry my edc shoulderbag* +extra knife(s) (it needs some upgrade for my FAK and that idea with the "stay alive cold kit" is something i might copy- page bookmarked) which would make things more comfortable in case of unexpected events. if i'm on a planned outing where i need a drink i carry my waterbottle in homemade carrier (see above) as well... (and often saw/SFA/nata if i plan to "harvest" timber or bamboo)
if out all day i add a daypack with needed items and on overnight trips more gear
+my faithful friend of more then 10years (=my walking stick)
*contents of bag right now: firekit (raku raku striker, flint, charcloth, short piece of jute twine, magnifying glass, matches in waterproof container)
silky pocketboy
torch
10m rapelling cord (in case i go exploring new territory and end up on top of a rock with no way around)
whetstone
cord
slingshot
waterproof container with bandaids (need upgrade here!), dunny paper, pencil and paper
if needed i also add a compass but here it's just downhill to get back to where i need to go...
