Well the plans to make one that are on ebay arent even for a real prop, it is for soccer gear on your arms, with a working flame-thrower on it.
Seeing one in action is just asking for trouble, it looks like it drips gasoline, and it lights, and BOOM, you have a flame-thrower, if you want to destroy your costume, and potentially hurt people around you (not exactly the person who asked the question) then go ahead.