Done! I scored this amazing vintage whitework for the ruffle. It's a finer quality than the body of the cap, but you can't immediately tell.
One more item done on the list. Next up is a bonnet and a turban. The turban should be super quick, and I don't anticipate the bonnet taking too terribly long, either. I'm going to do a gathered crown. It's perhaps not as common as a normal crown, but there are dozens of images of it in fashion plates for 1823-25.
From Journal des Dames et des Modes, available at http://digital.bunka.ac.jp/kichosho_e/