Tutorials/documentation about creating Qt-themes?
How can I make themes for Qt -- not the newer stylesheet way to do it, but actually drawing pixmaps(?) for the various widgets?
A tutorial or step-by-step guide would be best, but any documentation would be appreciated...
Well, of course you should see the whole QStyle documentation, the "reference guide":http://doc.qt.nokia.com/4.7/style-reference.html , the source code, etc. Apart from that, I'd suggest you to talk with the KDE developers for Oxygen :)
There is a chapter dedicated to this subject in the official Qt book "C++ GUI Programming with Qt 4":http://www.qtrac.eu/C++-GUI-Programming-with-Qt-4-1st-ed.zip