Some good ideas. My initial thought was a 'faced hole.' Depending on how large of a hole, one might be able to work it into a label. Have you read how or made a bound buttonhole? I'm thinking something like that might work. I thought you could make the quilt and perhaps even quilted it, keeping in mind where you were going to put the "hole." Once the quilt is finished, lay the 'facing square or rectangle' right side to the quilt top and stitch the circle or oval through all layers. Cut out the center and turn the 'facing' to the wrong side of the quilt through the hole and the facing will be right side out. You would want to turn under the raw edges of the 'facing' once it has been turned. Perhaps some hand stitching around the edge of the hole to mimic the original.
Janey - Neat people never make the exciting discoveries I do.