Michael Axel , Jul 10, 2006; 06:46 p.m.
I know the boards are the same, if you're talking about the 110x110 square boards. There are other boards that work too, like the Linhof.
One of the problems with the reflex housings on Toyos (and some other cameras) is that the springs in the backs are not strong enough to support the unit. As a result, the reflex device may not focus accurately because it tends to pull the ground glass away from the film plane. I finally sold mine a long time ago and chalked it up to "a good idea, but not practical".