My own meanderings in this field have been limited to a rather hacked Vocabulary Browser written in XQuery:
http://www.cems.uwe.ac.uk/xmlwiki/Vocab/index.xq
and my rather limited attempts to provide an RDF extract from the FOLD Information System.
https://www.cems.uwe.ac.uk/wiki/index.php/FOLD/RDF
with a current dump of the RDF