Configurable buttons for additional keys

Using both hands it's especially as a web developer with small hands hard to reach some important keys. It's easy for me to reach the first three buttons on every side, but the buttons I mainly use are in the middle of the keyboard :( It's hard to make such a keyboard fit for everyone, so it's maybe a better solution to make a custom set possible.

At first it would be great to have a possibility to change the order of the buttons, but really nice would be, if it's also possible to have 100% customizable buttons.