I like GraphDB. It would be nice if Skosmos can talk to GraphDB using its full-text operators.
See the documentation at http://graphdb.ontotext.com/documentation/free/lucene-graphdb-connector.html and also https://stackoverflow.com/questions/43517064/how-to-create-a-custom-analyzerfactory-in-graphdb-full-text-search.
I will investigate and provide a patch by looking at what already exists for JenaText.