DIY - Make a Duct-Tape Dress Form by David Coffin, THREADS Mag. Use Duct-tape as both the body-casting material & the final form. 2 different methods shown in articles. "Duct-Tape Dress Form" article & "more difficult "Closer-Fit Duct-Tape Dress Form.
Sew: How to make a Paper Tape Dress Form - Tutorial; A paper-tape dress form is the easiest and cheapest of all. This seems just a little easier than the duct tape dress form and a worthwhile project for a personal fit