Maybe think of building an RC2014 with CP/M. If it's completely self built there is another sense of specialty no prebuilt system can reach. And it's a good project to do together, too. There is also a variant with an 6502 instead of Z80 (RC6502), which can be built Apple I compatible.
https://rc2014.co.uk
https://github.com/tebl/RC6502-Apple-1-Replica