hey guys, try www.focusingscreen.com
also, can someone tell me what's so special about brightscreen?
Some say they are better, some not.
They use cut down Canon or other larger screens, and / or make their own. They treat them with a undisclosed process to be brighter than the ones Canon supplies for $45.00.
Making the best possible focus screens is a art, and it can be expensive to make really good ones, as opposed to merely milling down one made for a 1 series camera, or a Hasselblad, etc.