I've written a first cut at an ontology/schema for the plugin RDF: http://plugin.org.uk/ladspa2/ladspa-2.ttl
The term schema is a bit misleading, as it doesn't really enforce anything, it really just gives you some hints about what to write. The bulk of it is english text to explain the meaning of the bits that are no longer in the .h I tried to write it as clearly as possible, but the machine readable parts might still be a bit cryptic and there could be errors. Shout if there's any bits that don't make sense. - Steve