Here is a recent article of mine on Semantically Controlled Any-to-Any Data Structure Reshaping published in the new Semantic Universe web site that you may be useful. It demonstrates how ANSI SQL can perform any-to-any hierarchical data structure reshaping. These are transformations that are performed utilizing only the semantics in the data structure assuring correct semantic results. This transformation technique is used in XQuery for inverting a linear single path structure when no foreign keys are avaiable to back track. I have gotten this technique working for transforming nonlinear multipath structures in any way. I believe this same process may be able to be adapted to work in other XML processors. 

http://semanticuniverse.com/articles-semantically-controlled-any-any-data-structure-reshaping.html 

Regards, 

Michael M David
Advanced Data Access Technologies, Inc.
http://www.adatinc.com/