I'm not quite sure what this could be useful for. Working with xml in a browser isn't as easy as json, but it isn't so broken it needs another intermediate layer.
Thanks for taking a look. Working with XML isn't that hard, true, but even just using jQuery to replace my normal XPath looping-and-plucking was really nice. This just takes things one step further by letting you express collections and recursive structures directly in JSON. Instead of writing a function per XML structure you'd like to parse, you can write a single JSON expression. This project is barely 50 lines of code I think, so it isn't really too much of an abomination yet.