Hey Mike.. they are so cheap I don't know if it's worth the time to mix up the mix to make one myself. Plus it's pretty cool having a "model" of the ones that are being used all over the world to help rebuild the natural reefs.
CNN was at the factory last week and did a bunch of taping of the process. They are supposed to air the show in January. Once I know the date I'll post it back.
There are two LFS's here that are now going to be carrying these for local reefers.
Here's a pic of some reef balls and reef cakes after a short time in the reef. Notice the corals starting to take over and encrust on the surface.
(These are FULL size Reef Balls & Cakes)
http://www.reefball.org/newfrontpage/smallsizes.jpg