I would make the blocks out of the baseball fabric- 5 or 6 inch- with the dark fabric as sashing. As a border I would use the sashing with a narrow accent color like a red or yellow and then another border exactly like the sashing. I would make the binding scalloped out of the baseball fabric to accent the balls. It sounds very plain, but with all the other decorative details in the room I think it would be striking in it's simplicity. Use the accent color for a pillowcase and a throw pillow in the chair. Let the quilting design bring the quilt from plain to out-of-this-world! No simple stitch in the ditch or meanderings - go for broke with a good LA.