Thinking back a homebrew computer ( with a change in
the cpu card) was
in BYTE a 6800 or a 6502 machine.
The 6800 and 6502 buses are indeed very similar, so this does not suprise
me at all.
I think the UK-designed Tangerine machine had a CPU card with overlapping
40 pin IC pads for either a 6800 or a 6502 (you had to change the monitor
ROMs as well, of course).
-tony