Any public domain thesauri expressed in SKOS?

Do any public domain, general knowledge, English thesauri exist that have been expressed in SKOS?  Our company is developing a thesaurus in SKOS for the  domain of Critical Infrastructure Protection, and would like to supplement it with a general knowledge thesaurus.  We are an Oracle shop, and have taken a look at Oracle's thesaurus with an eye to using XSLT to convert it to SKOS.  However, our judgment so far is that Oracle's thesaurus is pretty bad.
Are there any "standard" thesauri out there, especially those that have been expressed in SKOS?  Anyone have any experience (good or bad) with any of them?
Please forgive me if this question is not appropriate for this list, since it has to do more with applications of SKOS than the design of SKOS (which is what the last few months of email traffic have seemed to be focused on).
Many thanks!  Enjoy!
John M. Linebarger, PhD
Sandia National Laboratories, Albuquerque, NM