Some of those shiny rayon and holographic threads would give you some great results, too. A nice cotton velour could substitute for the velvet, and polyester sateen with an iron on interfacing would work. If you have some nice decorative stitches, the background can be pieced, then crazy-quilted with fancy stitches, maybe varigated thread there.
Now I'm getting jazzed! Do you have any sketches yet?