Geoff Graham (friend, neighbor, and one of the founders of one of the finest new urban developments, I'on) accompanied me to Las Catalinas last week. He had lot's of great ideas, and followed up with this post on his Guild Quality blog:
http://www.guildquality.com/blog/2010/04/26/building-a-new-town-with-old-ways-las-catalinas-costa-rica/#more-1608