I made a bustle based off of the tournure in Corsets & Crinolines, sized it up and shortened it for a steampunk outfit. I made it with a cotton twill, and hoop steel.
I then made a skirt to go over top, and a bustle drape skirt on top of that.
Next time I would make the over skirt in a sturdier fabric, the lightweight cotton I used was just too light for anything but the underskirt.
You can see more about the construction at my Bustle Tutorial Page.