Carbine in a pocket and horrible death in a knife:

[jeffreyab]

Charles Stross pointed me at this video of an adaptation of a Glock handgun that turns it into a small carbine that folds up and that I could then put in my hip pocket.

Video here: http://www.youtube.com/watch?v=D99NHb6B03s

Charles also pointed out this nasty little number:

http://www.waspknife.com/about.php