The latest release of Metawidget upgrades our GWT support to 1.7 and includes a new example of running pure client-side GWT:
However if you don't need reflections or annotations, and have your own way of retrieving inspection results, you can plug in your own Inspector and keep everything client-side. This example retrieves inspection results from a textarea and generates the UI.
Download the example here. More documentation can be found here.