I can't speak for Mr. Parker but there is probably a good chance that there where black belt looking at ground fighting as a thesis topics prior to Mr. Parker's death.
I know that Skip Hancock and Kenpo 2000 has an excellent ground fighting curriculum that is American Kenpo - it uses the terms, principles, concepts, etc. to work on the ground position within the cycle of considerations. I know Mr. Mills has a similiar system.
I am not sure what Clyde is talking about specifically. If he could provide examples I think that it would be great. From my experience with Mr. Hancock, I known that I can "maneuver" while standing up and "maneuver" while I am on the ground. I can "be neutral" standing up and "be neutral" while being in a ground position. I can take the basics, principles of motion, and principles of self-defense and apply them from a standing position or from a grounded position (aka the mount, guard, north-south, etc.)
Is there an umpa (bridge and roll) in the base American Kenpo system? Can't see it. Is there the principles and basics in stand-up that allow me to implement the upma from a ground position. Yes. Perhaps this is what Clyde is referring too. Again, his comments leave a bit too much to the imagination.
As an example, tonight in class we will be working on "margin for error" or perhaps "with". We will work this from the stand-up perhaps through freestyle or the self-defense techniques. We will then go to the ground and explore the same concept from ground positions doing a self-defense technique from the ground.
I don't see, and it might just be my level of experience, the physical positions of the ground game in basic American Kenpo. I do see the strikes, breakfalls, and locks in the stand-up game that can be easily applied to the ground. What I don't see is the stances and maneuvers. There is nothing of course from stopping you from intelligently intregrating this into your system.
If you want to experience the ground game through American Kenpo and if anyone is in or near Bellingham,WA between January 21-23, Pacific Northwest Karate is holding an excellent grappling camp with Mr. Hancock, Scott Marker, and Joe Jones. They have incredible experience on the ground and have demonstrated Kenpo in the ground game to a great level.
Cheers,
Bryan