So, here we are. I finally have a way to make the costume without doing huge amounts of research. I'm talking about Kass' pattern, of course: http://www.reconstructinghistory.com/.

You can find an incredible amount of images here: http://frazzledfrau.glittersweet.com/cranach.htm.

The ones I prefer are below (all by Cranach):

UPDATE! I have a new love...

Portrait of a Woman , about 1525
Lucas Cranach the Elder
National Gallery, London: NG291.

This one is even better than the one below because it has the voided elbows, which Kass seems to think are unusual with the high-neck bodice. I wish I could find a higher resolution picture...


My very favourite is this one. I LOVE high necklines, because of the look, and also because I'm always more comfortable when my neck and shoulders are covered. I like the subtle bands of gold along the bodice front and neck too. As for the sleeves, I prefer the ones at the right. They're very similar, but they have the split elbow. The sleeves of the dress at the right are very similar to the ones in the image on the left, but they're split at the shoulder, revealing the chemise underneath. I don't know if it existed with the high neck dresses, but it sure looks nice!
Judith Victorious
c. 1530
Jagdschloss Grunewald, Berlin
Saxon Princesses Sibylla, Emilia and Sidonia (detail)
c. 1535
Kunsthistorisches Museum, Vienna
Judith with the Head of Holofernes
c. 1530
Kunsthistorisches Museum, Vienna

Now, for the colour. The ones above are all red, and most of the paintings we have are red. I've seen some black (might be a very dark green or blue), but I doubt I'll use it.

This one is red, but covered with so much gold brocade that it almost looks like it's all made of gold. A green one. I like green. It's less flashy than red, and is a colour that I wear a lot to start with.
Portraits of Henry the Pious, Duke of Saxony and his wife Katharina von Mecklenburg (detail)
Gemäldegalerie, Dresden
Judith with the Head of Holofernes
ca. 1530
Rogers Fund, 1911 (11.15)