Non-instant dry milk?
Some health food stores carry it. In my nieghborhood, one store has it, the other's never heard of it!
King Arthur Flour sells dried whole milk, $4.25 for an 8 oz bag. Here's the catalog copy:
Dried Whole Milk
Add richness and flavor to bread and other baked goods, yogurt, and homemade ice cream with Dried Whole Milk -- just as it comes from the cow, sans water. In 8-ounce bag.