Hi,

I'm interested in duplicating aspects of the forum layout and site design for use with bugs.kde.org. Is there a particular license on the CSS, images, etc. that I should be aware of before going through the time and effort to unify the look?

This is gpl work, so no problem, would be a honour if you use it (or parts of it)
The oxygen parts are lgpl, but you already know.

As an addition:

You most likely will implement a fluid version. I am currently working on fluid version of this. Maybe you just wanna wait a bit. If you'd like to have help, you can contact me on private (here or on irc).