I also did a great deal of sewing for Halloween. My Honey and I were Tony Manero and Stephanie Mangano from Saturday Night Fever. I modified My Honey's vest (it was originally gray) and made my dress from scratch, again, with out a pattern. It is not very fitted, so it was not too difficult to figure out. I am very happy with it.
I have also started working on my next bellydance costume. My sketches are complete, and some materials are purchased. I hope to begin work on the belt very soon. I will be sure to post my progress on that.