I think I am looking for something similar to what you are.
In more detail what I have been trying to research is a
lightweight concrete mix. I have heard there is a supplier of
such in pre-mixed packages similar to quickcrete. I've researched
making my own mixture. But right now a supplier of a pre-mix would
make it easier for experimenting with some of my ideas.
If you have any luck or if anyone else can help, please contact me.