Microsoft has been playing around with a language called Xen. It's a set of extensions to C# to manipulate XML and relational data. The article is fairly interesting to work through. It's an attempt to move the most common data storage mechanisms into the language. It's still only research at this point but it's a pretty interesting read.
This is a companion discussion topic for the original entry at http://billg.sqlteam.com/2004/01/23/773/