OOOh.. i'm always finding the solution after posting.. it pisses me off :((,
DVDSTORE example has urlrewrite :D
The DVDStore uses urlrewite to remove the .seam portion of the URL and to create /dvd/id URLs. This is done using bidirectional rewriting, which means nothing in the application needed to change to generate or consume the friendly URL. The wiki example also use urlrewrite. It uses fancier incoming rules, but I believe it doesn't use outbound rules.
We've got plans for a proper routing system for Seam 2.1 because, as you'll see from the dvdstore example, the rules get messy quickly. Regular expression matching is just the wrong technology for the type of rewriting we need to do in a Seam application.