Here's a tutorial for one.
http://sew4home.com/projects/bath-li...-secret-pocket

I've made one for my daughter. There are several free patterns on line. The bendy part of it is boning that you can get at Joann's. I think quilting it would make it a little heavy. Usually they are just a single layer of fabric.
My daughter did have me make a pocket on the inside of the cover. She used it for her breast shields.

OMG.....lololol

another one:

http://www.diaryofaquilter.com/2010/...-tutorial.html

The one I bought for my daughter was called a "Udder Cover"
:lol:

Well...you learn something new everyday when you call in at the quilting board! Been a long time since I was a nursing mother, but I don't think this would have appealed to me when I was younger.

I had a collection of very pretty lace shawls...generally black..used them to cover up then tied it over my skirt or slung it over my shoulder....bit bohemian, but that's how I dress anyway. Very useful when travelling and you can even fashion a shawl into a baby sling if you get a bit desperate.