Being a Martial Artist, as well as Fett Fan, I thought I'd chime in on this.. Check out this link. This will give you either a place to buy or some good ideas what you want to base a scratch-made from. Enjoy!
Asides from being a nasty weapon, a kama is also a legged type skirt worn by samurai, kendo, and aikido practitioners. AWMA also has them. However, while working on my clone commander, I simply got some material at the fabric store and cut it to look similar to a snowtrooper skirt !