I just published the wagon-svn project, a Maven wagon implementation that talks to a Subversion repository directly. This enables Maven2 users to deploy artifacts and push website contents to a Subversion repository in a fully automated fashion.
The main motivation for writing code is for our projects on java.net. First, the web contents of java.net projects are controlled under Subversion/CVS, so we had no easy way to do mvn site:deploy. Wagon-svn fixes this. Second, our java.net projects couldn't directly deploy to the java.net maven2 repository (see the linked page for the workaround we had to do), which wagon-svn also fixes.
I've been using this in several of my projects already (such as Hudson) successfully, thanks to a few folks who served as guinea pigs — Paul Sterk and Stephen Connolly most notably.
The docs on the site explains how you need to update your POM to use this for your java.net projects. Finally, if you find this useful, you might find my java.net skin project useful too.