Dear Andy,

You might want to have a look at VocBench, a web-based, multilingual, collaborative development platform for managing OWL ontologies, SKOS(/XL) thesauri, Ontolex-lemon lexicons and generic RDF Datasets. It's consumed by FAO's thesaurus (AGROVOC) and we have recently adopted it at WFP (not yet released though) to increase the visibility of our corporate Taxonomy and to improve the classification of content/documents within the corporate online applications that make use of it. Its browse and search interface, Skosmos, consists of SKOS concepts and uses SKOS and SKOS-XL predicates and properties.

I hope you'll find this information useful.

Best regards,
Francesco Iaizzo