For you guys thinking of carrying things, my older brother used to keep a mini-crow bar wedged between the engine and the tank. I'm not sure that he ever used it, but I think he did display it once or twice. Very effective.
I think that a much more practical solution would be a telescoping baton. Maybe velcro'ed onto the bottom of the tank. Key points: it's dull, so you won't cut yourself while grabbing it or in case of a spill, it's not evident, so you have less chance of police attention, and it could probably be used as a tool in odd circumstances... so you can justify having it.
http://www.defensedevices.com/aspbaton16inch.htmlA friend has one of these... (not for use with a bike) it'd be quick to swing & deploy, and various things would definitely suffer heavy damage from even a single blow. They're pretty heavy, and the 1-1/2 or 2 foot reach is easily enough to dissuade anyone who wants to go for a few rounds (especially if they have friends).
Then again, escalating the violence will probably get you in both legal trouble and increase the chance of retribution.
What ever happened to *losing* a pocket full of marbles over your shoulder at high speed?
I rather just spend 5 minutes hoping that they go find some instant karma all on their own. I'm also acutely aware of the fact that they'll probably pass my (very recognizable) parked bike at some point, and might want to do a little customizing of their own.
Francis