Have been working some more on the Semantic Web Client. I've started adding some real UI to it. It's not polished yet and it is quite slow at times, but it is finally getting close to doing something useful. I've added a history sidebar that shows a list of all of the resources one has viewed. Double-clicking a history entry opens it in the main content area, modifying the XUL and what RDF it is bound to accordingly.
It now has three datasources, Movies, Word lookup and Mozilla Bookmarks. The image shows some of the items from each in the history sidebar.
Next, I'll get it so one can add any RDF datasource at all, and get it so that links between them properly display the right UI for the right data.