The first dehydrated vegetable I ever saw was a dehydrated sliced potato. it was being used as a demonstration on how to rehydrate and use dehydrated potatoes.

It looked disgusting, gray and hard, in its dehydrated form. But she dropped it in a glass of water and an hour later it looked like it had just been sliced off a potato. Amazing!

I've not tried to dehydrate them myself, as I have a root cellar with a potato box and they keep fine there.