The biggest challenge is ion implant, which you can probably outsource to a lab.
Maybe I should just stick with FPGAs.
http://hackaday.com/2016/10/13/blinking-an-led-extreme-editi...
http://www.slideshare.net/junichiakita9/intorudction-to-make...
There some projects to realize low-cost, short turn-around-time LSI fabrication at slightly old process, such as 1um, in Japan, whose name is Minimal Fab. This will enable the (commercial) LSI fabrication service at a few hundred USD cost and 1-week TAT. I believe this a revolution similar to that happened in PCB world in ten years ago.
The fun part is that you can sometimes sneak an trial design into a shuttle service. ( but good luck making that initial design!)
IIUC he worked in the cpu business in the past but is too idealist to enjoy doing it now.
A fun example of a CPU built with discrete SMD transistors, the monster 6502 https://www.youtube.com/watch?v=tQIwS2GzXLI
There's also the MegaProcessor: https://www.youtube.com/watch?v=lNa9bQRPMB8
Zusie relay computer: https://www.youtube.com/watch?v=NXeBR-lbnjI