In case you still are looking for it, here's the link to the officilial DR distribution of CP/M-8000 tuned to the M20: http://www.cpm.z80.de/source.html On this page you will find the link to CP/M-8000 distributions

I have a few questions concerning the z8001 and accompanying software, may I get in contact with you about this (I am planning to build a Z8001 system myself (in the year 2002? Yes, because I bought the parts in 1985 and I rediscovered them just recently)