I have never seen one....but if I were to do it, I would mash a cup of sweet potatoes and add 2 teaspoons of salt to them.
Then mix 1 package of yeast with 1/2 cup warm water and stir in flour until it becomes rather stiff, but still able to be stirred, then stir in the sweet potatoes and keep adding flour until it's stiff enough to knead.
This ought to make enough for 2 10 inch crusts.
The crust will be very tender and not "snappy" and stretchy like ordinary dough.
I based my directions on a recipe for a rye bread made with white potatoes.
Lidna C