Amstrad made some that sold pretty well in the european market. They were Z80 systems. Their last model (pic) was a mistake though. It did have a rather fast Z80 clocked at 16 MHz, but by that time everyone was moving to PC and Win95 (pity too because I always like Z80 and CP/M more than x86 and Windows). They should have probably just gone into embedded systems or something instead. A lot of stuff ran Z80s back then, including many cash registers and those credit card swipping machines.
en.wikipedia.org
AmigaOS
That could literally also be said about Windows or basically any contemporary operating system considering they all need to be "almost" POSIX in order to work with a modern CPU architecture.
Also here's one of their TV ads from back in the day.
So, what is a good alternative OS to look into (Given the Linux is fucked)?
IBM OS/2
RISC OS on ARM processors.
Windows 98/XP on older hardware.
TempleOS on modern systems.
Make your own, it'll be fun. Imagine a world where trust in companies (and big projects like Linux) is so low and paranoia is so high that every tech literate person writes his own OS. It's what we're heading for, and I like it.
Windows and OS2 is literally nothing like POSIX.
But new Amigas are sold with PowerPC.
That would be awful. Everyone would be making Electron OSes and they would be taking 16 GiB of RAM all by themselves.