Using maven, one can push artifacts to central via ossrh; this requires GPG signatures, source, and javadocs in addition to the usual maven-deploy-plugin of the core jar.
Is there a recipe to arrange all of this with buildr?
We do this in Apache ODE so that artifacts comply to Apache's release policy and are accepted by Nexus. I assume that OSSRH works similar.
The GPG task used in ODE is based on a Buildr How-to document but is slightly extended to work. You can find it here. To sign all artifacts before upload, simply add a gpg_sign_before_upload to your toplevel project (see here for an example).