As someone who spent the better part of the weekend hacking up all of the Mapnik style XML files, it is great to see how someone gets things done more easily in TileMill.
I decided to go the mod_tile / Mapnik route so that I could generate tiles on the fly, world-wide. I have to agree that map styling is a huge time drain! Not only is it difficult for a map novice, such as myself, to figure out what all of the different Rules mean, but then the OCD takes over getting everything perfect. :)
Great write-up and really cool map style! I haven't even looked into customizing fonts yet. ;)