I just noticed this, very nice!
Just one question, is there any particular reason you used the DublinCore extensions for the RSS2 feed? I guess there may be fields you wanted to use that are not available in "plain" RSS2, though I couldn't see any.
Anyway here is a good example of non DublinCore-extended-RSS2:
http://www.jetbrains.com/rss.xml
Some elements are missing there like <language>, which is also available as a non DC alternative. If you don't know of one, I am sure I can find a site with a full list.
IMHO much "cleaner", but I guess it depends on what you want...