In my neck of the woods, products just like this but with civilian marketing and distribution are sold basically everywhere. The bag seems to be both alu-foil and plastic. The brands I have experience with are local to my location, but I guess you find similar stuff for sale on the internet if not locally. Quite popular among hikers around here, but not exactly high class gourmet, with flavors ranging from edible to will-do-if-hungry-enough.

I'm sure you can make a lot better stuff yourself...

Re-using those plastic/alu-foil bags seems like a better option than using the plastic bags of your vacuum sealer. A lot more compact and lighter than a pot, and a lot more reliable than the vacuum sealer bags. But with that option you haven't really eliminated cleaning from the equation.

A retort bag would be better. They are foil/plastic melded together. They will take the heat of boiling hot water without losing their structural integrity (melt). MRE pouches are retort, as are the freeze dried bags that actually direct you to add hot water to the bag with the food in it to re-hydrate.

Unfortunately retort bags are not easy to come by.

We also store dry parboiled rice, beans, flour in plastic bags, but I am afraid to cook in a plastic bag not specifically labeled for that use. I am not a chemist, but it is my understanding that plastic starts out hard, like bakelite, and a chemical softener is added to make it pliable. There are so many different formulas for plastic, and some are harmful when the chemicals that leach out are ingested. They have come out and warned against microwaving food in plastic, or drinking bottled water that got hot in a car. You might notice that plastic wares that are labled for microwave use are hard as a rock...no softeners. I remember hearing stories from WWII of wounded soldiers dying of 'shock lung', not directly from their injuries, but from tranfusions of blood that was stored in plastic bags. I know we're talking rice and dried foods and not blood and microwaves, but IMO it so easy to have a pot, bowl, or multi-purpose canteen cup along, that it's not worth the risk to me. I have washed out many a bowl in the sand and gravel of the lakes in the North woods and the Boundary Waters. I feel safer, and the little fish love me.

+1 on the ziplock freezer bag meals. I think with the vac sealed bags if you had a cozy you would be okay. IDK.

Thats why I stressed getting the name brand freezer bags.

I like the retort bag idea-not a clue where to find them, and they are likely far too expensive to be practical. I havent had any issues with the quality bags at all. One thing I recommend is using some sort of cozy-I have a GSI cookset, and the pot comes is a rubberized fabric bag-I use that as a cozy. Worst case, if the bag leaked, it would leak into the rubberized bag-and I would still be fine. I am sure an insulated mug would work too, if it were large enoough.