Found this photo as I was trying to organize the digital clutter. I took it at Late Night stitch-n-bitch, back when I lived in Oregon. I thought it was so clever!
Instead of a sleeve: make triangular pockets in the top corners of your wallhanging, then cut a yardstick so it fits snugly. I suppose a length of inexpensive wooden trim/molding or off-cuts from a lumber yard could also work. And the *genius* final touch is to attach picture-hanging hardware to the center of the wood, so your masterpiece can be hung on a simple nail.