I've emailed a zip of the xml to the mods, and hope that it can thus be added for your further exploration.
Ed - the point about scalability is simply a caveat: I have no idea if this technique would cope with (say) a For-Each SSIS container with this source query used within it, pointed at inherently large XML files. I have not explored this because - well - it's Spackle. It works, the source files I am using are inherently small, and I have no reason to go any further. YMMV is the best advice.
Eirikur - I have absolutely no doubt that this crude little script could be optimised much further, or substituted for by other techniques. But my client is not interested in paying for any such work, and I am too busy to be interested on my own account. It works, end of story for me. However, the beauty of fora such as this is that others are quite free to go the extra mile and post their improvements.