This idea may or may not be of any use . . . but many years ago, my daughter had a cloth doll, which was very love-worn, to the point where I was afraid to even wash it. I took it apart and sewed a lightweight lining to the fabric, which greatly eased the stress on the seams. Just wondering if that would work on a quilt top. The lining could be carefully hand-stitched "in the ditch" and possibly strengthen it enough for quilting. Like I said, it's just an idea and may or may not be worthwhile.