I just finished watching an episode of Boondocks that features an homage to the titular weapon from the classic Kung-Fu movie Master of the Flying Guillotine. http://youtu.be/jejQ1wJ_oeI
It got me wondering how one could build such a weapon for PF. I was thinking:
Flying Guillotine
Exotic Light Melee Weapon
Cost: ???
Dmg (S/M): 1d6/1d8
Critical: 19-20/x2
Range: 30 ft.
Weight: 8 lbs
Type: S
Special: Vorpal
In order to have the vorpal ability, this would obviously be a magical weapon. It would be nice to build it without resorting to magic, though...
They did it on mythbusters too.
I don't think it would need vorpal. I would say it does 1d10 damage, 20/x6 and it can only be used by making a called shot to the head.
With a critical hit, it could do enough damage to take the head off.