Thanks to everybody for their input!

stewer: That makes a lot of sense, since that is the only info I found when looking up .cg files in Google.

estherau: I had not seen those before.  I was very thorough in checking out toon/cel shading resources a couple of years back, but have not researched recently.  Do you know if olivier's shaders function in the way I was trying to accomplish?  Do the light and dark color adjust their shade depending on the intensity of the light, or are the colors fixed and show for a fixed range of intensity?

The reason I am thinking about this is that the way the default toon shader works in Poser, you need to change the colors that you assign to light and dark for different lighting situations.  They don't adjust appropriately on their own.  For a bright, outdoor scene, your dark color will be only slightly darker than your light color.  For a darker room, you might want to leave the light color the same, but darken the darker color due to the smaller amount of ambient light in a room.  For a scene where the character is in a spotlight with no ambient light, the light color should be very bright and the dark color should be almost black.

See what I'm saying?  Wouldn't it be nice if the shader just chose the light and dark colors for you appropriately based on the lighting situation?

Thanks again for all your input,

-digitani

Check out my website: http://www.digitani.com