That is an Awsome idea!
I've heard of this before plate before, but never really knew what it was. I think it would bea great tool to help train portion control.
You can can do the same thing with just a regular 9 inch plate. Divide your plate in half and put veggies on that half. Divide the other half in half and fill one quarter of the plate with your protein and that last quarter with a starch. Easy and much cheaper! Examples at: www.platemethod.com
We have a wellness center at work (I joined WW at Work last week) and the people I know (met) who use the portion plate said it works for them. Knowing the me that I am, I would try to stack up within the confines of the dividers...LOL! J/K! Are there directions that say you can't pile the food up past the plate's edge or anything like that?