Laura,
I only bought the large Sennelier in a black. Other than that none. If you want big pastels, Dakota Art Pastels (
www.dakotapastels.com) sells the medium and maybe large Unison pastels. Those are wonderful.
The Great American pastels are somewhat like Schminkes, but have a larger and more coherent color line. Their skin-tone pastels are the ones I seem to end up using the most. Their Midnight has the darkest most velvety deep blue of any of the other manufacturers.
Dakota also has handmade charts of all the pastel lines. They are invaluable if you are looking for a particular color or trying to file a scruffy looking orphan. I put them in a loose-leaf binder.
Let us know of your progress in this endeavor. It would be really interesting.