Here's a way to use directional border fabric in a string block as the center strip.
I used scissors to cut the paisley print fabric you see into 13 1/2 inch strips and placed each one down the middle diagonally on 12 1/2 inch foundations of muslin.
I then did the sew, flip and press method, sewing darker fabrics of varied widths on one side of the paisley fabric and lighter tone-on-tones on the opposite side.
Here you can see what four block look like with the paisley seeming to give a framed look.
Here is the final quilt top measuring roughly 80 inches square. I love this look and now always look for border fabrics in a different way.