Despite technology having advanced greatly. I dont' think I've ever left the 8-bit world of the early 1980's.
In recent months I've put together the RC2014 which is a Z80 based backplane computer. It is expandable, has 64K or RAM, 64K of ROM and can run the CP/M operating system from a Compact Flash card.
It has also had a box made as I didn't want it lying on the bench and getting damaged.