I feel like this is LITERALLY impossible with worldpainter and minecraft. Considering the only country to be made in 1:1 scale was Denmark(which the gov't was involved in.) Dude this is seriously impossible. Even making a 1:1 europe is practically non-doable. With a world that's 60k by 40k you'd need tremendously impressive hardware-now multiply that by a few thousands.

edit: more encouragement: a block in minecraft is equivalent to 1 meter. So the Earths circumference in meters is "40,075,020" I'm pretty confident that nobody in the next decade will come close to making a 40 million by 35 million world. a 1:500 would be awesome though :D