Apple has applied for a trademark on the phrase "Made For iPod" at the US Patents and Trademarks Office.
The application was filed August 10, and seems to cover every category of iPod peripheral, even those that seemingly lack the dock connectors currently covered by the scheme, such as "carrying cases, sacks, and bags".
The application also suggests further extensions for the product family. It describes: "A full line of electronic and mechanical accessories and computer software for portable and handheld digital electronic devices for recording, organizing, transmitting, manipulating, and reviewing text, data, audio, image, and video files."
The application also includes a scheme logo and effectively describes a branding scheme.
Sources suggest Apple intends extending the scheme which it launched earlier this year.