I think if you search around the net for:
MCW (Meal, Cold Weather)

You'll find some sources. Of course, if you're not US Mil, you can't really buy them legitimately. EBay, doesn't seem to care however.

They used to be called MCW/LRP (Meal, Cold Weather, Long Range Patrol) but they are apparently two different rations now. Lots of current US Ration info is on:
http://www.mreinfo.com/us/current/current-us-rations.html

The MCW/LRP info sheet from the Natick Army Labs:
http://nsrdec.natick.army.mil/media/fact/food/mcw_lrp.pdf

That's one thing that I've never needed - even in the land of eternal winter. I guess it's just too dry here to get moisture freeze up in the lock.

I actually never needed it either. I lubricate my lock with lock spray and my door seals with a rubber stick (?) thingy. I carry the little defroster more for others...

Minneapolis gets that cold drizzle that turns into ice,i had to use crowbar to open my car door.i hate to say it but sometimes i'm just not prepared!!
shingles make good grippers to drive out of icy spots.

That works fine for a car. In most modern cars the mechanical lock is about to become a secondary solution anyway. Most people use the radio control in the key in my neck of the woods.
Motorcycles however have a remaining risk of lock freeze ups even when the locks are lubricated. When that happens while the key still is in the lock, the trick with heating the key can´t be applied.
The motorcycle also requires an extended pre-ride check to make sure that all of the controls work smoothly both ways.
When I drive my car, I do not even carry defroster anymore.