I love your find! Perhaps I should be going to yard sales, too! My quilt guild used the black fabric at one of our meetings to make Christmas ornaments. Each member got two identical squares. Then you fussy cut out the medallions. Next you put one on the top of a styrofoam ball and one on the bottom, gluing the overlap. Finally you cover the heck out of it with all types of beads. They are beautiful! I'd show you a picture but mine is still a UFO! Perhaps this will inspire me to finish it!
Another member used the same material as a whole cloth like you are planning. It was beautiful, too! Enjoy the quilty possibilities.