I had a pretty good idea, that will definately be practical.
Take the tazer, it has one shot effectively, and the personal ones often have a point blank range (excluding backpack based water tazers and plasma tazers)
I think I am going to build myself a tazer whip for self defence and such.
Something along the design of a reasonably short bullwhip, with metal, or better yet, carbon fiber, strands to conduct the electricity running along the length of the whip, perhaps a sharpened metal barb on the tip, sort of like a stingray spine, or a chunk of barbed wire etc.
Have a transformer and replaceable PP3 type battery in the handle, and you have yourself a pretty vicious shock-whip, I imagine any mugger confronting someone with a weapon like that is going to squeel like a b$*%( and run away pretty quickly
I think it might be a good idea actually, instead of having one barb, have four or more strips of carbon fiber running down the whip length, connected to an equal number of sharp, but short metal barbs, so as to enable production of a "demonstration" crackling arc, to provide for a feature to just scare the potential assailant away, the actual sight and sound of a high voltage arc snaking all over the whip would look pretty damn fearsome I think