Has there been any work to define an XML subset which is
simply/directly transformable into JSON?
I know there are many XML expressions that  are very difficult to
convert to JSON due to limits in JSON that make such a conversion very
messy, but I would guess that with a number of standardized
restrictions, that might be easier?
Just wondering... I'm seeing more and more situations where I need
that kind of 'more direct compatibility'.

- Brian