And then, on the last weekend before the con, I finally made it. Just the wire rebato, not a new outfit (perhaps another day). I decided I could wear it with some 16th-century things in my wardrobe, in particular, the rebato could hold up the 1590s ruff quite well.
First, I sketched a design of three bats in a semi-circle the same size as the existing ruff. Then I used black millinery wire to make the rebato. Much twisting with needlenose pliers and fingers ensued. Took a couple hours, and I feel like I could do better. Pretty good for the first one, and the concept worked very well. I added ribbon ties that pinned at the front of my gown, and the rebato held the ruff up quite nicely all day.
Bat rebato worn with 16th-c. outfit at CC27
Back view of bat rebato, photo by Koshka
Completed bat rebato