Jean-Jacques Dubray of http://www.ebpml.org/about.htm is becoming one of my favorite blogs. I have only followed his blog the past couple of months. I admire him because he is one of a few technologists that attempt to step back from the platform specific SOA implementations and discuss SOA from an agnostic viewpoint. I just finished reading his book Composite Software Construction (http://www.infoq.com/minibooks/composite-software-construction). The book is easy to read and touches on several SOA topics as well as insight into the history of the WS-I standards. It is free and certainly worth your time. Jean-Jacques is also behind the WSPER specification, which he covers in his book (ref. http://www.wsper.org/). WSPER appears to have a lot of potential and something to keep an eye on.
While catching up with the thousands of blog subscriptions, my interests were peaked by a post from Jean-Jacques blog - http://www.ebpml.org/blog/30.htm. Apparently, Xcalia offers an SDO API for both Java and .Net - http://www.xcalia.com/products/xcalia-xdas-data-access-service-SDO-DAS-data-integration-through-web-services.jsp. SDO is similiar to the .Net DataSet but with a twist. Jean-Jacques states in his book that the .Net DataSet is based on an Entity Relationship Model and SDO is based on the Hypergraph Data Model.