Discrete Component
From T729 Balanced Ternary Computer
Building a discrete component ternary computer implemented in BCT would actually be quite doable with fast switching SMT MOSFETs and cheap custom PCBs.
NPN/PNP CMOS logic gate layouts would result in low power usage. It would not be a cheap project but there is no reason it would not function if obviously build correctly.
Another option is using standalone fast switching discrete SMT logic gates.
If I ever get around to learning how to create my own custom PCBs I want to explore this more. Start by making little modules that act like a SUM, ANY, CON, etc ternary gate. Later design bigger PCBs that slide into a black plane like computers of old. Each board making up the functions of a full ternary computer.