I am looking for a martial arts school in the greater Seattle area
that practices the Okinawan Shorin-Ryu style of Karate.  There are
three subdivisions of this style (that I'm aware of): Kobayashi,
Matsubayashi, and Shobayashi.  Although I would prefer to find a
Kobayashi dojo, this is of lesser importance than finding a genuine
Shorin-Ryu school.

Hello gerasim,
  
I was able to find one dojo that offers classes in Shorin-Ryu Karate:
  
Wheeldon Karate School  - http://www.wheeldonkarate.com/
  
Address: 3920 N.E 10th Street, Renton, WA 98056 USA
  
Okinawan Karate is taught by Roy Wheeldon, 2nd Dan in SHIMA-HA SHORIN RYU.
  
Phone: 425-271-1985 / e-mail: roy@wheeldonkarate.com
  
Schedule:
http://www.wheeldonkarate.com/schedule.htm
  
Lessons are $60 for a set of 8 (50% discount for additional family members)
  
  
I also found another instructor listed on the Ryukyu Bujutsu Kenkyu
Doyukai (RBKD) website:
  
RBKD - Seattle Branch
  
Instructor: Richard H. Waddell
8301 South 180th St.
Kent, WA 98032
  
http://www.oshirodojo.com/directory.html#wa
  
It states here that Richard Waddell has been training since 1980 in Shorin-Ryu:
http://www.shorinryu.com/Newsletter-Spring-2004.htm
  
  
Other links:
  
Shorin-Ryu Karate USA Home
http://www.shorinryu.com/
  
Open Directory - Shorin Ryu: Schools and Instruction
http://dmoz.org/Sports/Martial_Arts/Karate/Shorin_Ryu/Schools_and_Instruction/
  
  
Source: 
  
RBKD Dojos Directory
http://www.oshirodojo.com/directory.html
  
  
  
I hope this helps.
  
Best regards,
  
Jackburton
Google Answers Researcher