The CKAN data portal software now has fully integrated output of metadata as RDF linked data, in XML or N3 format. To see it at work, simply add the appropriate prefix to the URL for a dataset. For example, here is a dataset on the DataHub (as it happens, part of the LODcloud). Would you like an XML RDF file of the metadata? here it is!
Instead of changing the URL, you can also change the “Accept:” header of your HTTP request. For full details, see the CKAN documentation. The new feature is already live on the DataHub, and will be released soon as part of CKAN 1.6.1.