Togakure ryu Bikenjutsu is it's own beast. Steve Hayes books would be a pretty bad example, imo.
Each individual style of Kenjutsu, whether it Ninpo or not, is very unique to the Ryuha itself.
In Togakure ryu, a very short shinobi-gatana is used. The blade is 21 inches, yet the tsuka and tsuba are normal size, as well as the saya. Much of it uses batto(draw cuts) off of an attackers cut or strike. The full length tsuka/saya give the impression that it's a "typical" sized katana, yet with the size it's very quick to draw, cut and move on.
Sword schools across the board have their own "isms". Kukishin ryu Bikenjutsu, Shinden Fudo ryu Biken and Koto ryu Kenjutsu also have their own ways of doing things.
The only school that I've ever studied that strongly leaned on another art was Shinto Muso ryu, which was because of the founder studying Katori Shinto ryu.
