These are the results I got with modifying Simplicity's cape pattern #2499 (might be discontinued, but check eBay). I widened the center back panel so that I could accommodate the pleating. It also widened the hem some. My finished hem was just short of 18' - that's a big cape!!
I used Baroque Satin and silver lamé fabric. The collar has an inner layer of fusible Pellon 71F Peltex. I bag lined the entire cape - which means I sewed the sides and bottom with right sides together like a pillow case before attaching the collar. The hem is completely closed in.
My preference is to not put a closure on the front, but if you're wearing it outside the show you can easily add a large hook and loop or tie strings.