A bulk hot chocolate mix recipe like those below probably won't win any culinary awards, but the local Boy Scout Troop will probably think it dandy.
Hot Cocoa Mix
10 c powdered milk 1/2 c cocoa 1 1/2 c powdered sugar (or less, to taste) 2 lb instant chocolate milk mix (Nestle Quik, for example) 6 oz powdered cream
Mix and store in airtight container. Use about 1/4 cup of mix per cup of hot water.
Camp Hot Chocolate
6 c powdered milk 1 lb instant chocolate milk mix (Nestle Quik, for example) 8 oz powdered cream 1 c powdered sugar
Mix and store in airtight container. Use 1/4 cup of mix per cup of hot water.