Thank you for the link. It was worthwhile doing some research into TileMill (which I heard of but did not see the connection).
But one the the constraints is that the output has to be EPSG4326 (ll84), and as you can see from this support request:
http://support.mapbox.com/discussions/tilemill/122-projection-support-wanted
The MapBox people are not interested in anything other than WebMercator right now.
But since TileMill is just built on MapNik, and they spit out the XML style, it might be possible.
Right now, I have heard that FME 2014 will have direct MapNik support, so that is what I am looking at. Since FME is much more polished than the GDAL, python, C++, NODE etc stack that the MapBox, MapQuest, and MapNik solutions that I am seeing, but I keep looking at this stuff.
Obviously, with a 9 level deep world map I need something that scales, which also pushes me to FME.