I've been looking at some of the instant meals in a box that you can buy at Woolies or Coles.
They're in a cardboard box with a couple of plastic pouches inside. The idea is to microwave the pouches and mix them in the little carton.
I can't see any reason you couldn't heat the pouches in a pot of water (like a retort pouch).
There's a couple of brands (I like the Woolies home brand) and are basically pasta or rice and a sauce with bit of chicken or beef in them.
They're a bit heavy at 350g odd but a bucket load cheaper than dehydrated meals.