Happened upon this article about some guys looking at beating the endurance record, 64 days 22 hours. For some reason they are looking at a Cessna 172, seems to me a Carbon Cub would be a lot better and safer for the low and slow refueling.
http://www.usatoday.com/story/news/nation/2013/04/14/flight-endurance-record-attempt/2080991/