The following two links are related to my Skribler project.
The first shows the work of Kirill Osenkov on a structured editor for C# (though not limited to C#). The videos are especially nice to watch, as they show some of the benefits of going for structured editors. What I'm missing here is an idea of how easy it would be to set up additional languages with this editor.
The second link is for Citrus which is a tool/programming language for setting up structured editors. There is video of it in action here. Unfortunately the tool is not publicly available.
Makes me feel that I should get back to work on Skribler...