I've been making my own for several years using the following recipe I found on the web:
Emergency Ration Recipe
By: various survival sites
* 3 cups rolled oats, barley, or wheat
* 2 1/2 cups nonfat milk powder
* 1/2 package Jell-O powder, citrus
* 1 cup sugar
* 2 tablespoon honey
* 3 tablespoon water
Preheat oven to 300 degrees. Heat together water and honey, stir in Jell-O powder. Stir dry ingredients together, stir in Jell-O water, mix well. Then add additional water 1 tablespoon at a time, just until mixture can be formed into two bars. Dry in oven, wrap in foil to store. Each bar is 1000 calories. May be eaten as is, or cooked in a pint of water.
I divide them into 9 smaller bars, Press'n Seal them, and toss them in the freezer.
I left one out of the freezer to see what the shelf life was and it went about 18 months before developing any mold.
I prefer the lemon flavor but lime and orange are good too. I've been meaning to try vanilla so I should do it while I'm thinking about it.