Find an old tennis racket. Take a the racket to a glass shop and ask for a custom-cut beveled-edge mirror that fits inside the rim. Squeeze Liquid Nails Mirror Adhesive onto the back of the mirror. Firmly press it onto the strings. Let dry overnight.
Tutorial: How To Make A Circular Mirror With Wood Slices http://theownerbuildernetwork.co/bn73 Mirror, mirror on the wall... looking for a weekend DIY project? Then this mirror could be just what you're looking for.