I promised the last one Kamina will be the last try for my ultimate keyboard, and it was indeed so close to the ideal that for a time I considered the project done. However, I found just two little things that could be improved, so inevitably, when I was ordering PCBs, I added this one more to the order:

So what changed? First, there is one more column on the right hand side of the keyboard, so that I can have my ";:" and "+=" keys on the base layer. Second, there is an extension header in the middle, which can be used to add a variety of modules, from a PSP joystick, through an encoder with a knob, a display, or even exotic stuff like a gesture sensor.

I moved all the switches and components to the new PCB and amended the layout: