It's available now (http://taubz.for.net/code/semweb/).
See:
http://taubz.for.net/code/semweb/semweb-current/apidocs/SemWeb.Inference/RDFS.html
And for a quick way to get a SPARQL server with RDFS:
http://taubz.for.net/code/semweb/semweb-current/apidocs/SemWeb.Query/SparqlProtocol.html