You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
Yes, it is very easy to expose REST style bookmarkable URLs in a Seam application. In addition, the Seam application can initialize all the necessary backend business logic and persistence components when the user loads that URL. This way, the RESTful URL is not only an information endpoint but also an application interaction start point.
If you just want nice looking URLs, Seam integrates a URL rewriting filter that can manipulate URLs when rendering a page and do internal redirects from GET requests. The bundled dvdstore example shows that feature.