This is odd and fascinating at the same time: a native port of CP/M for the 6502 processor with additional support for relocatable binaries. The odd part is that there isn’t really software for this, as it will not run 8080/Z80 code.
Currently, it runs on the BBC Micro and on the C64. The port is based on LLVM MOS tool chain, but the developer, David Given, expects to provide an assembler and an editor for the system, eventually.
There’s also a series of videos on the development: