This is just too good; I got this link from someone for a totally unrelated reason at work, but saw the Road Pig reference and I just had to share:
http://www.theawl.com/2011/08/that-maps-all-wrong-for-youI've known for a while that little non-existing alleys were put in maps for copyright reasons, but had no clue they did it with whole towns, too. And that Road Pig came from one of them!
I wonder if Hama knew this all along and this is part of the joke (which wouldn't surprise me), or if this was just a coincidence as he pulled the name of the town from a map.