[masklinn]

I'm not sure what you're trying to say. The source of the data is irrelevant, XMLRPC w/ nil (and other pre-existing formats I'm sure) are strict supersets of JSON, any JSON document can be converted back and forth between XMLRPC and JSON without data loss. So XMLRPC (or something else with similar capabilities) would give you exactly the same ability to apply XML tools to "JSON sources".