I love the marble idea. I'd rather buy and store one marble than a whole big thing to go behind the quilt - the less stuff I have to find room to store, the better (I'm a bit of a pack rat and already have enough stuff!). Can you buy a single marble? That's mostly a rhetorical question, I'm sure I can figure it out. It seems like it would make it easier to pin or hand baste, as well as protecting against scratches. I'm always worried that I'm not getting all the layers when I pin.