Some type-specific sailplane canopy resources in the US:

Aircraft Windshields, Inc, in my experience the best in the aircraft
transparency biz:
Los Alamitos, CA, no Web site
--Gliders various, just ask (incl. 2-seat Lark, I think)
--Custom tooling and acrylics

ThermoTec (Ray Poquette), advertises special UV protection:
http://home.inreach.com/thermotc/
--Libelle (just be sure and insure your shipments)
--HP-14
--Various others, ask
--Custom canopies with tooling charges

Todd's Canopies, makes free-blown transparencies of reasonable fit,
low prices:
http://toddscanopies.com
--Russia
--KA6
--ASW20(?)

Wings and Wheels:
http://wingsandwheels.com
Mecaplex and Josef Weiss dealer, stocks sliding window kits, rails

Marske Aircraft, Marion OH:
http://www.marskeaircraft.com/
Sign up for his seminars, he can show you how to do simple free-blown
transparencies
--Pioneer
--1-26

HP Aircraft (me), Arnold CA
www.hpaircraft.com
--HP-18 (one-piece)
--RS-15 (only one left)
--HP-24
--HP-11 by special arrangement

Thanks, Bob K.