I would stay away from the head stone and go with the bargello idea. do it from grays to maybe blues of a sky with a lovely yellow starry burst in the center and maybe have the names quilted into it. this way it is more of a memorial instead of something sad looking. that is at least how I feel about headstones. You might need to make 3-4 quilts to fit all the names on them. I would make at least two, one for each "front". you might for the backing want to get military material for each branch that is fighting and piece it together. but this is just a loose idea that came to mind for me. you will show us what you end up doing.