2300+ Homemade Dry Mixes ~ this is the motherload of all DIY mixes on the web! These are broken down into 31 categories and include hundreds of "convenience" mixes like cake mixes, taco seasonings, copycat recipes... wow!
Homemade Cream-Style Soup Mix Recipe from Taste of Home Recipes. Dry mix stores well in an air tight container for up to a year. From comments: It starts out thin but thickens up nicely. For a can of soup equivalent, use 1 1/3 cup of water to 1/3 cup of mix.