You son of a... I'm on my first playthrough of Fallout 3 right now and I just spent all the time I was playing today trying to find a clutch to make that damn thing. I've exhausted all the vehicle places I can find and the junk vendors don't seem to stock them. I also stumbled on serveral new locations and completed several side quests all in persuit of one item. Don't tell me though, I still want to find it for myself, but at least now I know that the reward will be all the better for it when I do finally get it.
The Tesla Cannon sounds cool as well. I guess that'll use the Electronic Chargepacks I've been saving up all this time. And I've been sinking plenty of points into E-weapons, so that's great!

Also, if you want cool sound effects, you should listen to the TF2 weapons, because they are amazing. Personally I like the sounds of the Sniper's rifles, because you really notice how they incorporated the different uses of the weapons into the asthetics.
There's the regular, which sounds like a normal sniper rifle. Then there's the Sydney Sleeper, which fires its darts with a sounds like a tribal man shooting a dart through a piece of hollowed-out bamboo. There's the Huntsman bow, which Yahtzee pretty accurately described the sound of in this column. The Bazaar Bargain, which sounds like a powerful blast of thunder. And finally the latest Machina has a forceful metallic clank coming from its muzzle flash supressor. And they all make fantastic sounds in their own right.