I agree that for purposes of demonstration, an 8x10 is easier to see the affects of tilts, but I think it would be more valuable to keep it in the context of what your students will be likely to be using. For that, I agree with eveyone else, it's hard to beat the Calumet, and even if you do, it will still work afterward ().

Stuff like yaw-free tilts and all the numbers on cameras like the Sinars will just confuse noob's, IMHO.