a great implementation of this kind of big world is Asheron call 1 (microsoft) the map in this mmorpg is really huge, but you can run from a part to another without any loading except when you enter dungeons or enter portals.
i don't really know how they do the trick but it really inpressed me when i was playing this game.well it's an old game so the graphigs are a bit rough for actual standards :)
i don't really know how they do the trick but it really inpressed me when i was playing this game.well it's an old game so the graphigs are a bit rough for actual standards :)