My brother and I I got my mom a food dehydrator last Christmas. Now that fruits are starting to come in, she is experimenting with it and learning how to use it. One of the biggest successes was something that she had never planned on or thought about drying: mulberries.
We have several mulberry trees in your yard. They came with the house. Aside from taking out nests of tent caterpillars, we don't do anything to maintain them. I will sometimes eat the mulberries when they are fresh, but nobody else likes them. So all the fruit simply serves to feed a massive flock of cedar waxwings.
But when my mom saw the birds feasting on the fruit, she decided to pick some and dry them. It worked out really well. Mulberries are very easy to pick and dry, and when dried they have a great taste and texture. They are also a really healthy fruit. So I am now picking all that I can, and drying them.
I've never seen mulberries, fresh or dried, for sale anywhere. This is probably because they are difficult to store and transport. I'm sure that there are hundreds of great foods that never appear in supermarkets because of things that have nothing do do with taste or nutritional value.