this blog posting gave me some indirect inspiration. Design Sponge uses a threadless sewing machine to stitch holes into a piece of card, something I've done before but had pretty much forgotten about.
I appropriated the idea and used it to punch holes for the letters, using a pin for the curves which were too tricky for my machining. The stitches are either chain or Holbein, with a buttonhole wheel for the 'O', and some french knots on the flowers. All in all, fairly quick and fun to do.