I'd been given a couple yards of this machine-pleated blue tissue-lame (on a bonded backing that could be peeled off if so desired). While not a perfect color match to the blue glitter vinyl, it was close enough to use for the sash
Yup, you read it right -- I have a cell-phone pocket hidden in the sash.
All that is left now is the greaves. bovil persuaded me that the silly hat I had in mind would add nothing to the costume, and suggested I make a silver laurel wreath instead. That will actually work with either mk I or mk II. I will still probably make said silly hat, as it is a perfect PenWAG show-and-tell item. It just doesn't have to be part of this costume.