This seems to be pretty similar to the "System Settings" layout found in Kubuntu. Are you sure it's universal to KDE 4? kcontrol is the default in KDE 3 and looks like this:
Which is much more versatile than the System Settings panel in either Kubuntu or OS X, if you ask me.
I found it in a screenshot walkthrough of KDE 4. It could always be a theme... but I just found it interesting. OS X owes a little something to it's UNIX heritage anyways (ie. 3d dock and multiple desktops)... maybe it's fair that something UNIX/LINUX takes a little something from OS X (theme or not 😎 )