Rows can be very different between different layouts. The modularity of a generic row-module would be somewhat limited to specific layouts. Additionally it woul

Rows can be very different between different layouts. The modularity of a generic row-module would be somewhat limited to specific layouts. Additionally it would enhance cost and complexity significant, while reducing certain practical aspects of such a design. I don't think todays technology is really there yet for a good enough solution. If you wanna see a step into this direction you can look at the "Ultimate Hacking Keyboard". They have a collection of modules to be attached on the side of the keyboard. You will also see some of the problems of such a design there. Personally I would aim more for single-key-modules. Make lego-like parts for a keyboard where each single key can be arranged on a board as you wish, like with lego-bricks. Does also scale far better across all used layouts, because at the end you have only a handful module-types which can be used for all designs equally. Makes mass-production cheaper on the long run.