You really should spend time looking at an RDF dump and the documenation before proceeding.
Kids and Teens is available separately.
However, since categories cross reference back and forth to other categories on different top level cats, you would end up with references [for example] from within Art going to Business, should these be left in or not? If you leave them you are creating an incomplete RDF dump, if you leave them in, you are not strictly within Art, and you cause bloat from repetition of information in each dump.
The bottom line, is that in my opinion it will not happen. There is already too much work involved in creating the current RDF dumps, creating one for each section would probably more than double that effort.