I'm just amazed that I never posted about this project on my favorite hacking site, Hackaday.
I've already completed the project, and there are hundreds of units making music all over the world. But no hardware project is complete until it is posted here...

A haxophone is an electronic musical instrument that resembles a saxophone. It is designed to be an inexpensive and fully customizable travel saxophone. You will never get the same expressiveness or depth of sound of a real saxophone. But with a haxophone you should be able to play alone or with friends wherever you might be. The mechanical keys and unique ergonomics give it a different kind of satisfying feel.