I don't know if this is the same thing, but you may be interested in this failed project from IBM in the 1990s that attempted to leverage Taligent and OS/2 to create a universal operating system that used a microkernel and was capable of presenting different UI and programmatic "personalities."

https://en.wikipedia.org/wiki/Workplace_OS

Yeah, I think that was it. Most of what I remember from that era was the pile of printed OS/2 programming manuals on my desk.