Oxygen font family is already available for testing (currently in alpha!) and comes with regular, bold and monospace variants, however, only the basic character shapes are done for now and the font is currently using the basic 'auto spacing' from FontForge.

Oxygen Appmenu is an Oxygen style for Kwin that displays the application menu as a button in the titlebar and works with Qt and GTK applications as well as Firefox or Thunderbird:

KDE 4.6 was supposed to ship with a transparent Oxygen style but in the end it didn't make it "due to serious issues (notably with embedded widgets, such as videos) which cannot be fixed at the style level". But that doesn't mean you can't install Oxygen-Transparent. Read on!