Properties for media fragment?

Hi all,

I had a look at the very impressive working draft of the media fragments wg.
This section
http://www.w3.org/TR/2009/WD-media-frags-reqs-20090430/#MediaFragmentApproaches
made me think whether we could benefit from two properties
spatialMediaFragment
temporalMediaFragment
and potentially
namedMediaFragment
the mappings are already in the section cited above, inclding the potential
return types for the API.

Comments?

Felix