Just did that before the holidays, the only thing to add there is probably the firmware. I'm curious what other recommendations there are, but I found TMK (https://github.com/tmk/tmk_keyboard) to be pretty nice.
Checkout QMK, it's what TMK is based on and overall is more powerful. However, both are great tools. BootmapperClient and several others are also very good.
Checkout the HHKB or other Topre switch keyboards!