Still not ready for anything real, but definitely making a step forward is the FOSS music tooling platform, a.k.a., JFugue Music NotePad, now sporting for the first time a new guitar feature (a work in progress), thanks to Johannes Reher from Munster (click to enlarge the image below):
When you click on the keyboard or the guitar, the relevant notes are added to the score. You can create multiple scores, which are automatically assembled into compositions. A composition consists of multiple scores, which can be played together, though that part is also a work in progress. Synchronization between all the various windows is something I worked on most recently. I.e., select a score and the related composition node is selected, while the related content is put into the JFugue command window.
We're working on the 7.0 branch, which can be checked out here:
Anyone want to plug in their own music tool? You're more than welcome to do so! Especially if you know how to do music notation correctly in Java, i.e., all the notes need to be connected, etc, rather than separated, as they currently are. An enhancement in that area would be really useful.