Thank you, I will write and publish much more documentation as soon as possible :-) It is a four layer PCB, one for Vcc, one for ground and the other two for signals. I designed it in KiCad and ordered it from PCBWay.com.
I will also upload the schematic etc. if anyone wants to have a look or create one their self. However, if anyone wants to build it, it may be a bit expensive due to the high IC count.
Five PCBs cost me $250, but they can be made cheaper. Otherwise the price depends a lot on the components. Ceramic ones are very expensive and the whole computer would probably end up at around $300 - $400. For plastic components, the price would be more close to $200.
I will also upload the schematic etc. if anyone wants to have a look or create one their self. However, if anyone wants to build it, it may be a bit expensive due to the high IC count.