As a VisualEditor plugin inside the extension, provide a visual way for users to create and edit musical scores.
This would be a (very) major undertaking, even if there is an existing JavaScript-based visual Lilypond score editor, or failing that, a visual score editor with a different output format which would need to be converted to Lilypond. A brief search found a few promising leads for ABC editors, but mostly based in Flash.
Still, hopefully not just a pipedream. :-)
Version: unspecified
Severity: enhancement