Now you can have icons and wallpaper from new Android KitKat without even running on this version.
Unfortunately, the Android 4.4 has not been released yet, therefore not all of the icons are available.
Currently available icons are: Google Now, Google Services, App drawer and Dialer. All of these icons were copied from Android 4.4 leaks and I must admit, they are accurate.
Android 4.4 Icons with wallpaper:
Files are available on the cloud in .png form. To install these icons, you need to be running on custom launcher supporting this feature = Apex, Nova and much more others. To change the icon, just simply swap and select the icon from the gallery.