Could Apple (OS X) wallpaper be licensed for commercial use?
Apple and/or Apple’s licensors own the images, as stated under Apple's Software License Agreement for Mountain Lion:


  The Apple software (including Boot ROM code), any third party software, documentation, interfaces, content, fonts and any data accompanying this License whether preinstalled on Apple-branded hardware, on disk, in read only memory, on any other media or in any other form (collectively the “Apple Software”) are licensed, not sold, to you by Apple Inc. (“Apple”) for use only under the terms of this License. Apple and/or Apple’s licensors retain ownership of the Apple Software itself and reserve all rights not expressly granted to you.