I worked with CP/M in the 1970s.
Don't think that'll help though, since it didn't last long after IBM picked Microsoft's OS over Gary Kildall's CP/M. Kildall didn't last long either, sad to say.
How about the Mac OS on a PC? I don't have any experience with it, but I've heard about people doing it. A google of "mac os on pc hardware" got lots of hits, and among them was one that jogged my memory: the OSx86 Project. If you're interested, that's where you should start, I think. And please post about your experiences.