Stretch lamé is a suitable alternative to leather - and easier on the wallet. You can use any mens brief as your pattern - just add a dart in the front crotch seam, and diagonal seams across the cheeks.
I added 1¼" wide straps on the sides and center back. Be sure to secure them when you create the elastic casings.
To create the elastic casings in the waist and leg holes I used flesh-colored, single-fold bias tape - make sure you stretch the fabric a little as you apply it. Applying to the right side of the gold fabric I used a ¼" seam allowance then turned it to the inside to stitch. Insert ½" elastic into the casings (adjust to fit).
I recommend securing the rhinestones with a dab of jewel-glue. Once the glue is dry it'll be easier to maneuver the rhinestone mounting from behind.
Detailed photos of the original shorts can be found on the Anal Retentive Costume List.