While reading Paul Wilson's blog I discovered
that he has written an open source ADO.Net XML provider: WilsonXmlDbClient.
It apparently "enables Xml to be worked with just like a database in .NET. It supports
the most common Select, Insert, Update, and Delete SQL syntax, as well as tranactions
and parameters."
What I really like about the idea is that one should be able to easily reuse the OR
mapping structure that has been created for a project when dealing with XML.
The downside is that it requires inline SQL which I personally dislike in my data
access layer.