B Ethan Davis Had this comment:

I like the single 'OPeNDAP' service idea with the requested foundation service encoded in the request message. I wonder if the DDX should contain a more generic request message rather than one specific for the Blob, e.g.,

</Dataset>
    ...
    <RequestMsg SrvcURL="http://hostname/axis/services/OPeNDAP"
                dataSetName="data.set.name">
            <Constraint>
                ...
            </Constraint>
    </RequestMsg>
</Dataset>

That way it doesn't limit the type of request a user can build from the DDX info (or rather, it doesn't give the appearance of limiting the users request).