The open source version of the C128Neo called Open128 has now been released, you can find it on github. This is almost identical to the revision 3.3 of the C128Neo, with changed logos.
It is licensed under CC BY-SA 4.0 and can be used as you please, feel free to issue pull requests if you have improvements.
There are issues with the silk screen but it should be functional in any case. I have not had any boards manufactured from this design but the only functional change compared to the C128Neo is that jumper J4 is now connected to A15 instead of A14, allowing the use of C128DCR ROMs.
I’ve also managed to find and reverse engineer one of the unusual 128CR boards. This was a cost reduced version of the wedge 128 that was never officially released and seems to be completely undocumented in general.
I’ve already captured the schematic which is largely based on the 128DCR board and am working on replicating the PCB now.
This work will also be released as open source once completed.