The jacket was actually the first thing I finished. While I was still at a loss for what fabric to use for the dress I found a curtain in a charity shop that looked good for the jacket. It was the wrong colour, but it looked like it might take a dye and be a reasonable approximation.
I don't have a really good photo of it, so this will have to do for the moment.
I'm very pleased with the construction of the jacket, even if the colour isn't quite right, and it's not quite long enough. After careful study of screenshots, I'm pretty confident that this is very similar to the way the original was constructed. If you can't tell, it's a rectangle of fabric with the bottom corners brought up to the side of the neck, then sewn to the top edge from collar to cuff.
Now, I have about a metre and a half of rope to sew on by hand, so I'd better get back to it.