Not a backyard foundry but this guy is attempting to make a "tangible" RISC-V CP...

Not a backyard foundry but this guy is attempting to make a "tangible" RISC-V CPU using "As few programmable chips as possible." he wants to use MSI and LSI chips " so things like buffers, flip flops, and so on. "

More details: http://www.halfbakedmaker.org/blog/lmarv1-1

YouTube playlist https://www.youtube.com/playlist?list=PLEeZWGE3PwbansoxKjjMK...