Hi Sarah, thanks for the cake love, these are also one of my faves and fun to make. The cutters are easy to find, they are fmm sports and music cutters, I dont know where you are situated but here is one example of where to find them in Oz: http://www.cakesaroundtown.com.au/catalog/music-sport-tappit-cutter-p-1815.html
I cut them out and painted them with edible silver lustre then used ‘pipe dont paint’ silver icing to paint the silver lines, you can also make your own silver icing too. Hope that helps, good luck!!
Janette, Jake's Cakes, www.facebook.com/eatJakesCakes