I'm posting this in the current craftster challenge. Kat had the link to the site, I saw it, and a few weeks later...
One twin-size fitted sheet from when I was ten, two nearly-empty spools of thread, and my circa-1980s Pfaff, inherited from my aunt via my mother.
It needs some alterations to be worn alone, but with a top and a cute sweater, it's ready to go. I think I'll wear it to work tomorrow.
Maybe tomorrow (when I'm not dozing), I'll post how I did it. I made many mistakes along the way, though, so my instructions may be lacking.