All the stunguns I,ve seen on these pages are very dangerous for the operator. Either you get one in and it tickles your adversary enough for him to realise what it is and put your lights out, or he puts your lights out while you're waiting for it to charge. If you really want to build a weapon, consider some keywords. "Ni-MH batteries" "flyback converter" "boost converter" "SMPS" "ferrite transformer" "welding arc initiation""photoflash capacitors" "flashtube trigger circuits" "series trigger for flashtubes"
With that lot you should be able to build something that starts with 50Kv to get an arc going and follows up with a big cap bank at a kilovolt or so to make smoke. And, furthermore, charges in well under a second.