RDF should allow XML datatypes

RDF datatyping should allow the form:

http://example.org#foo http://example.org#prop "<this>is some structured
XML</this>"^^http://example.org/SomeSchema#myType

where http://example.org/SomeSchema#myType identifies the XML datatype:
element this{text}

Similarly RDF/XML should provide for:

<rdf:Description rdf:about="http://example.org#foo">
    <ex:prop rdf:datatype="http://example.org/SomeSchema#myType">
            <this>is some structured XML</this>
    </ex:prop>
</rdf:Description>


1. There is no compelling reason to prohibit this given the current RDF
datatyping solution for which this is a minor modification to the syntax.
2. Allowing this will be very useful for OWL which needs to deal with
structured datatypes
3. Despite the face that XML Schema does not _automatically_ provide for
URIs for schema particles, when it does in the future, and when one
explicitly assigns a URIref to an XML Schema particle, this solution will be
most useful.
3a. The failure of XML Schema to provide URIs should not arbitrarily limit
RDF datatypes. Indeed such a failure will arbitrarily limit future RDF and
XML Schema datatype interoperability
-- 2 specifications would need to be fixed not just one -- both the current
XML Schema REC and the new RDF REC
-- there wouldn't be so much reason for XML Schema to provide URIs for
complex datatypes since RDF wouldn't be able to use them.

Jonathan