I'd like to create a new theme based on the oxygen theme (using the oxygen theme as a template for the new features of the theme like tabbed windows found in KDE4.4. RC2.)

Can anyone point me to where the actual theme files and config files are located. I did a search for oxygen but didn't really come up with what I was looking for.

I'm particularly interested in where things like the image files for the scrollbar arrows, minimise and maximise buttons, and other decorations are located.

KDE and Qt have this written as actual code in C++ for maximum flexibility. As such, there are no "images" available.

You can change the colour scheme though.

Thanks for the reply. So if we want to make a theme and be able to use the window tabbing feature will this be possible or is that also hard coded?

Unfortunately I do not know if the Aurorae window decoration ( which provides the SVG based window decorations ) supports Window tabbing.

Note that the Oxygen window decoration is written in C++ also.
It is up to each Window Decoration to decide if it wants to support Window Tabbing.