Buster SwordI don't think it's quite wide enough, or long enough, though.
Another BusterThat one's better, but has more than just two materia slots.
I can't find anything on the AC version. It's probably too early to get it. Besides, I think the blades didn't exactly go together perfectly. Whenever he added a sword to the main one, there was this funny glow along it, like it was literally merging or something.
I'm quite interested in Kadaj's sword. It doesn't seem like a feasible sword, because the blade typically extends into the handle and is pegged to it by a bamboo pin. Judging from AC, the blades end at the hilt, which means it's not exactly a sturdy build.