Well you can always add a 7 1/2 border to top and bottom made out of pieced 6" log cabin squares. You could set them straight with a border strip on top and bottom or put them on point for even more length.
Another options is to make big beautiful pillow shams and throw pillows to match and don't modify the quilt length at all. Simply place it on your bed lower down and cover up the gap at the top with the pillow shams and throw pillows.