No not a musical keyboard, you know like QWERTY with … well chords. Mathias is looking to speed up his productivity on the keyboard. Some people just switch to DVORAK (which he looked into) but he decided he wants to make a special keyboard. When you read his article you will discover his journey of ideas and options, but to shoot to the end, he decided to make a HID device using a Teensy. The Teensy is a awesome arduino compatible microcontroller that is pretty good at making usb devices.
Anyway, the project isn’t complete yet. He does have some preliminary source code up and some test code, but it looks like he’s working on the meat of the project (the keys) next.