I think it would be cool to be able to find hidden treasure. Maybe it could give you secret blue prints that would unlock more research potential or maybe some sort of awesome item, or just cash and other resources.
I think it would fit better with this thread: http://ludeon.com/forums/index.php?topic=1032.0 (http://ludeon.com/forums/index.php?topic=1032.0)
As for acquiring the map maybe a rare drop from a pirate raider?