UPDATE 11/22/14 @ 5:45PM EST: There is now a download link.
I made a Minecraft highway which has pretty much what you might expect a real highway has. Much of the structures in the system is based off the New York State Thruway, and it already looks very cool. It takes about 27 minutes to walk the entire length of the system, and it's (95%) designed to handle horses. Also includes some real life stuff too, including cities/towns in New York.