Re: Designing Sword Schools
From a purely creative standpoint, virtually all martial art styles started out with a philosophy or inspiration that dictated how the art developed. Wing Chun was based on 'occupying the center', the space squarely in front of the opponent, and deflecting opponent attacks to make room for your own. So lots of blocking and punching, very little dodging. Bruce Lee's philosophy in developing Jeet Kune Do was speed through economy of motion--lots of quick attacks and a more emphasis on dodging. Tae Kwon Do's philosophy is that the legs are much more powerful than the hands and so the legs are the primary weapon in that style. Brazilian Jiujitsu contends that most real fights wind up as wrestiling matches anyway, so it concentrates on takedowns, holds and locks. Aikido's philosophy is one of redirecting your opponent's energy and using it against him and consists almost entirely of block/throws and joint locks. And let me quote Wikipedia on the differences between Northern and Southern Shaolin kung fu:
That's all unarmed combat but sword styles are the same way. Ittosai's philosophy was one of simultaneously blocking and attacking with the same sword motion. Musashi's was that people have two hands and should use two swords independently (but by most accounts Musashi was huge and had fewer str min issues). I'm not up on fencing but I know the lunge was designed as a quick, efficient in-out attack from range; Bruce Lee was inspired by that maneuver.
So to design sword martial arts out of thin air, just make up philosophies of your own and go from there. An art based on entanglement with sword and main gauche would have disarms, blocks, and holds. A style based on attacking the foundation (feet) might have trips and high-dcv strikes. One based on the scorpion would have one-hand grabs and overhead strikes. YMMV.