A floating field of... Something

I started this as a material test. I created a mushroom shaped object, textured it, rendered it, and I liked the look so much that I duplicated a several more and did a little node compositing with it.

I think I am going to add a background, and also add a little more variety to the mushrooms. Right now they are all the same, but I would like it to be a little more random in shape and size.