Is there such a thing as svn:externals which works within a single repository? i.e. can I "mirror" directories within my repository? I'm building a J2EE framework and this would be quite a handy svn feature so I can buildthe project website in the same repository alongside it.
EDIT | Forgot the smilie

EDIT 2 | Actually I think a more sensible option will be to simply "merge" any changes back into the trunk manually.