Hi Marcia! I have been wondering how your Bargello was coming. Keeping it for yourself is a good idea....since your son has a new quilt in mind.
I made a Carpenter's Star ...
http://www.quiltfrog.com/fourhour.html ....that was pretty easy. It has a center that could be made out of one fabric, like you are describing. That is if you can find fabric that you like for it. Take a look, in case it happens to be what you are looking for. It does have half square triangles, but they are big and the quilt goes together rather quickly.
Maybe I can find a picture of mine....might help too. Yup, though you would want to change the center. Look at the pattern, and I think you will find it is pretty do-able. (Ignore my quilt inspector Hot Rod and his mouse toy. I couldn't keep him out of the picture. I kept throwing that mouse to distract him, and he always came back...)
You are a good Mom, you know.
Dina