You must be joking

> The best means we have for identifying media type right now is MIME-types. Unfortunately, they are really too incomplete and disorganized for CCP purposes. Their ontology is only two levels deep and highly incomplete.

You might be interested to check out Apple's solution to that problem, Uniform Type Identifiers (first introduced in OSX 10.4, it's been slowly introduced into more and more data transfer APIs). They are multi-level hierarchical, where the hierarchy is defined outside of the type-name.

http://developer.apple.com/library/mac/documentation/File...

Also see the "Pasteboard Concepts" article.

http://developer.apple.com/library/mac/documentation/Coco...