Quantity   Component name
1 × 1970s era mainframe Romanian, Bulgarian, Eastern Germany or Soviet-Union made if you find it in the Eastern Europe. Rough and tough, hard to repair, reliable when you get it working.
1 × 9 track tape drive Western Europe or USA-manufactured - preferred. Big pain if you get the communist variant.
1 × STM32 development platform Get as many GPIOS as you can
1 × Arduino...whatever Any of them able to handle 8-bit ports. Arduino Due is extremely fast but the physical ports are a mess. However the ATSAM3x8E by itself should be a treasure