My friend Cindi does a lot of t-shirt quilts, and she uses Pellon 906F for them.
You know what my first thought was when I read your question? How cool would it be to take those silk scarves and make 3D flowers out of them to sew on the quilt.
Here are some previous threads about quilting with silk, you might find your answer in one of them:
http://www.quiltingboard.com/main-f1...s-t227789.html
http://www.quiltingboard.com/main-f1...s-t210904.html
http://www.quiltingboard.com/main-f1...k-t245532.html