I feel like I was fairly successful making my own colorburst powders. I have a half used Rose Art watercolor set from the school art supplies, and I just took a razor blade, scratched off the surface of the cakes, then collected it on a piece of thin paper. I was then able to sortof tap it onto my paper.
It is not as pigmented as the colorburst and similar powders, but I might be able to get more pigment if I scratched off some of my Koi watercolor cakes?
So anyhow, I have a background done, and now need to decide what to do with it. I was able to get the embossing powder to stick by sprinkling it on the very wet paper. I used watercolor paper, if that makes any difference.