if you go to http://www.waleapparatus.com/index.asp?category=18738, you can buy hollow glass tube.. when you get the tube score it with a file all the way around and crack it off to get the length you want and with a propane torch slowly heat up one end while rotating it and it will close up. stuff a stailness ball bearing in there after it cools, then chuck the tube in a non electric hand drill and heat the other end up until that closes.. dont crank the drill but turn it back and forth to keep the glass from dripping...
Rattles, Ive used them in tying flys here are the ones I use there realy light an are 1/4 round an 1'long, you can get them WallyWorld, --> RENEGADE 20 in a box. havent tryed them in a plug yet.
GOOD LUCK GOOD PLUGGIN