Large Stand-Up Cozy Ideas?

You could divvy up the meal before hydrating and let every body 'cook' their own. That'd be one less item your party as a whole has to bring.

I think you should be able to use the ti pot immediately. The laws of thermodynamics say that since the pot is full of boiling water the pot itself should stay more or less at boiling temp. Since your plastic bag can handle boiling, and the pot will have cooled slightly by the time you've taken it off the flame and poured the water out, it should be cool enough not to harm the bag. Worth testing in the kitchen first though ;)

Otherwise I'd suggest making something out of aluminized bubble wrap, available at many hardware stores and lumber yards. Here's an example: http://sagebrush-trails.com/food-cozy-pot-cozy/ With a little creativity you can make something that will fold flat when not in use and it will have enough structure to stand upright when full.

Using the pot is definitely the lead contender. Second would be a large cozy. I think this would be less weight than rehydrating in three separate containers. Thanks for your thoughts.

Reflectrix is a brand name for the shiny bubble wrap. At the national home improvement stores, you have to buy the whole roll. At a hardware store, you may be able to buy it by the linear foot.