what stunning fabric.
i would do something along the lines of a marble floor.
there's a book and patterns on the market by the name of Bella Bella Quilts.
you might get some great ideas looking at the designs and many of them utilize large panels in the center. there's a gallery section on the website and you can see the large panels and what people use for blocks around it - here's a link
http://www.bellabellaquilts.com/home.html