The Eclipse consortium has launched the Visual Editor Project, "a new effort to create and deliver an open visual GUI construction and editor platform. The project is dedicated to generically supporting any user interface framework and programming language supported by Eclipse, and will initially implement a reference GUI builder for the Java Swing/JFC and SWT graphical user interface frameworks." The current version is 0.5.0, a very development milestone based mostly on contributed IBM code. It's all open source, naturally.