I purchased a 405nm laser diode (Blue/Violet - almost UV) off ebay just recently and needed a case to mount it in. So I have turned this from a length of aluminium tube for the body and two pieces of aluminium bar for the front and back closures. The front closure doubles as a heat-sink. Everything's held together with grub-screws. Runs off two AAA batteries which just fit inside.
I think it looks a bit like a light-sabre!