There are a number of efforts to make low volume production of compatible parts - see https://github.com/rejunity/z80-open-silicon https://github.com/rejunity/z

There are a number of efforts to make low volume production of compatible parts - see https://github.com/rejunity/z80-open-silicon https://github.com/rejunity/z80-open-silicon There are also FPGA emulated versions.