The problem is that you can't just take any yellow belly and breed it to any granite and get an ebony. If that were the case, then yeah, everyone would have them by now. There's something else going on with it.
It's great to hear that Graziani has been able to reproduce them, that's something I wasn't aware of. It was always a little disappointing to see a picture of the ebony knowing that it was apparently a fluke. Hopefully he'll be able to figure out what's going on with it genetically and start working it into some combos.