craftgrrl | Halloween costume question

I am attempting to make a Valkryie costume for Halloween.

Alas, I am in need of a breastplate.

this website: http://www.britta.com/costumes/Valkyrie/index.html says that she was able to make it from a plastic torso form from a swimsuit she bought at Costco.

This I have checked for, and alas, they no longer have them in stock.

So!

Any recommendations? I've purchased duct tape with the idea of doing something like the sewing dummy, but that promises to be a long and arduous ordeal. So any other ideas would be fantastic. Thank you :)