stack icons into a composite image

It would be lovely to be able to stack multiple icons into the same image. Each icon could have a different color, alpha, shape and size, and the resulting image would be a composite of the various icons. In this way, we can create FAKIcons that have varying transparencies within the icon, as well as different colors within the icon. I don't know if others will use this, but I need it for my project! :)