I have multi module Maven project. Modules have own trunk/tag/branch structure.
So the Hudson checked out not only the trunk but also all branches and tags. It
is not so convenient, especially in case of parallel development in several
trunks (branches). I see several ways to resolve such situation:

1. Checkout (and check for updates) modules according <scm> tags.
2. Introduce filters to include/exclude scm paths from checkout (updated)
process. Similar feature implemented in FishEye to segregate the
trunks/branches/tags for SVN
3. Use the second way but for Maven projects build the filter list automatically
according the content of <scm> tags.