Cordell Baum's "Electric Dread" fly...
OK, it's not every year I get a chance to fish saltwater...but I'm considering that plastic material that is used for a the shellback might work for a freshwater crayfish imitator?

Maybe in the orange, or a green...or maybe a yellow (I don't know exactly what colors it might come in...). Could be a very useful pattern for smallies or even carp, too!