Geta, love the new pics you added and I'm waiting for your instructions on your blog. I'll mark my calendar. It appears that the technique is just like how I learned to do machine quilt only you use organza on the top. I've also seen shadow trapunto done using regular muslin...of course the bottom fabric is a really strong color and shows through almost as a pastel. Interesting.
I'm IN LOVE with your bags now!!! The shadow trapunto really lends itself to them.