I cannot seem to upload the picture so there is a link. I was thinking of either Brushed Black Metal, Matte Black or Matte Red for plate colours.
That's a really cool-looking design. I like it!
Depending on your base colour for the headphones, the different coloured shields would match differently. I think it would look best on a matte-black shield though.
I posted the story/design of my shield a few pages back.