I have seen this done. The fleece blanket I saw had 4" added to top and bottom. Then a solid colored fleece, the full length of the panel + 8", was sewn, right sides together, leaving a slit at the bottom. Them turn inside out. Sew up the slit and top stitch about 1 1/2" from the edge all around the whole thing. It looked great and made it long enough for a guy.