It's not going to be exclusively available for ultra billionaires, if it is possible at all. There are lots of things that would be powerful advantages if only a tiny elite had access to them: vaccines, antibiotics, anti-retroviral drugs, digital computers... but if a thing is demonstrated possible at all, others will figure out how to do it again. And if the first inventors refuse to sell or share the technology it will just be spread by the second or third group to figure out the trick.