I love OS X Aqua style, and I use a combination of elements to create an environment which looks almost exactly like Panther.
A. Get SmoothAkua w/ OS X button placement from kde-look.org at
http://www.kde-look.org/content/show.php?content=9228 and install it. You'll need to use IceWM as your window manager.
B. Download the Baghira style and install it. It adds many OS X like features, including stripes to the kicker (which you hide later) and an OS X scrollbar.
C. Get the Karamba Mac OS X Bar from kde-look at
http://www.kde-look.org/content/show.php?content=5609 and, before installing it, get superkaramba from
http://netdragon.sourceforge.net. Then, extract the OS X bar to a folder, open superkaramba, and run macosx.theme. From now on, it will always automatically start at startup.
D. The only thing left is the KDE kicker. You have two options for this. If you prefer to keep the kicker, then hide it by right-clicking on it, selecting "Configure Panel" and select the Hiding tab. Select the second option to hide the kicker and select immediately, then press okay. Voila! The kicker, (almost) only when you need it. Or, if you prefer, uninstall the kicker via your package manager.
Have fun!