Painting of a beautiful dress form: - Storefront Life - Storefront Life Shields this painting made me think of you. I think you should paint your vintage dress form onto that large canvas you have, maybe with that old prom dress you have.
Take 4 canvases of each size), paint them a solid base color and add vinyl or stenciled design. stick decals onto canvases, paint the whole thing and then remove the stickers to reveal the wonderful artwork!
Here's a fun little canvas I made using some of the new Doiley rub-ons. It's really easy to make, and you only need a few supplies; Doilies Rub-ons Blank Canvas (mine is x Decoupage First cut out some.