Seia Ryu ( 雖井蛙流平法 ) is (at least for me) a very interesting Ryu-ha. The Ryuso Fukao Kakuma studied a countless amount of Ryu-gi earning a Menkyo Kaiden or equivilent in most of them. He made an unussual choice when formulating Seia Ryu. That choice was to borrow kata from other Ryu. Keep in mind they are not exact copies, he modified the techniques but kept the ideas of the parent Ryu.
The style is structured as:
Goran-Tachiwaki:
1) Shaku-jyo (Kyosui Ryu)
2) Inazuma (Togun Ryu)
3) Kyoko-Ryu (Shinto Ryu)
4) Kineta (Aiden Bokuden Ryu Ichi no Tachi)
5) Katanami (Shinkage Hikida Ryu)
Kodachi-Juzan:
1) Tetei (Matsumoto Ryu)
2) Enpuku/Enfu (Shinkage Ryu)
3) Inretsu (Moni Ryu)
4) Saifu (Nen Amida Ryu)
5) Seka (Toda Ryu)
6) Ratsutaku (Shinkage Ryu)
7) Sodan/Satan (Toda Ryu)
8) Usen (Taisha Ryu)
9) Sakan/Saketsu (Taisha Ryu)
10) Itto Ryodan (Yagyu Ryu)
Sankyoku-Tachiwaki:
1) Kotakakaeshi (Iwa Ryu)
2) Tamasudare (Yagyu Ryu)
3) Shuran (Toda Ryu)
Gokui no Ken:
1) Shinmyo-ken
2) Fushigiken
3) Riryoken
4) Seizan/Hoshikiri
I have seen them demonstrait several times and eachtime I was greatly impressed, exspecially with their kodachi stuff. Prior to that video I have only seen them do up to Inazuma of Goran-Tachiwaki and Seka of Kodachi Juzan. So I am quite happy. Also on a side note: the current Soke of Seia Ryu is also a Menkyo Kaiden in Shinkage Hikida Ryu Sojutsu/Naginata (Something else I would really like to see). Seia Ryu uses both bokken and furuko-shinai. They also have produced several skilled kendo-ka (their previous headmaster was a 8th dan, hanshi in kendo).
There is a good article on Seia Ryu Heiho on Aikido Journal:
http://www.aikidojournal.com/article?articleID=171
It only skims the surface of Seia Ryu but it is a good article.