Thanks to Old Git, I found myself before in Argos (whilst picking something up for the nephew) flicking through the back pages looking at LP cases.
Then when I went into B&Q for some wood preservative, I was drawn to the plumbing section and found myself staring at copper piping.
I'm now weighing up whether I can fashion something for the side of the ninja! So Keith I hope the patents pending, cause i'm stealing your idea