My artistic achievements are nothing to boast about, but I have put together a couple of wallpapers and pictures that are posted here, as well as one SuperKaramba theme for anyone looking to make KDE (on Linux/*nix) look more like Mac OS X. Note: Everything here is released under the GNU FDL (see here).
Generally, click on the images and "Save Link As..." to download them
Again as posted on KDE-Look.org, this was taken from another wallpaper on that site and put on the brushed-metal background. As above, 1024x768.
Mac Top Bar
If you need a full screenshot, go to this page. It's a SuperKaramba theme that emulates the OS X top bar, but incorporates a taskbar. I modified it from Luis Maraud's theme (also found on KDE-Look.org), and added a configuration script (from a terminal, run "./config.sh" in its directory) that lets you set certain parameters, such as screen width, bar style, the clock, etc. All the relevant files are in the .tar.gz package. (Of course, you need SuperKaramba to use this!)