4x3 + FN and 3 LEDs Macropad

As usual nobody modelled the exact specification of what I want in a macropad so I did it myself. 
It has space for the number 0-9, comma and period. 
The top row is for a Function key and 3 LEDs which visualise the current layer. Basically, this pad has space for 46 macros. Even more if you do some smart visualizing. 
Another plus is, that a Arduino Pro Micro has 18 IO pins and this thing has 12 buttons and 3 LEDs which equals 15 IOs. So you can even omit the diodes if you want. 

Feel free to reach out if you want the software for the Arduino. 

EDIT after building it: 
In V2 I'd give myself a little more space for soldering it. Additionally, I would make it slanted so it fits better with my keyboard. The USB hole needs to be a bit bigger and I'd make the bottom plate nicer so it fits flush on the table. The plate for the switches needs to be thinner as well, but they hold good nevertheless.