Finally i had enough free time to work on the PCB layer, here's the first version (unverified for now)
click to view the whole layout
Since I can't etch something >300mm, I have to split each board in two parts.
So we have the logic boards (74×4094, and uln2803) on the top, and the "matrices" boards (with the led matrices) on the bottom.
The power board (with the mosfets), and the controller board (with the µC) are still in dev.