SO, I toddled down to my local fabric store, bought myself a pattern, some satin and elastic, and here we go! Let's see how it works.
(Note: this may wind up being the 3,078th project to sit half-finished in a bin under the spare-room bed. I'll keep you updated.)
(Note #2: The pattern picture is from a site called "Fabric Indulgence and Art Supplies." Fun stuff!)