I wanted to make a quick reply to my post about foam earlier in this thread. Marty's Hobbies on Moorpark Road in Thousand Oaks carries a number of items for prop making, including rigid foam, foam cutting tools, balsa wood, ect..
I've known about the place since I've been in the area, but didn't think to look there for foam. Turns out RC Airplane enthusists use the stuff to make planes.
(The soft foam in fabric stores is great for padding, but not really rigid enough for sword like props.)