Okay, I don't know whether this should be in the D20 Games forum or the Minecraft forum; a reddit poster says he uses Minecraft for D&D mapping:
Quote from: http://www.reddit.com/r/Minecraft/comments/tw6iw/my_current_basepositioned_above_a_ravine_work_in/c4qd3bm
Love it, did something kind of like that in my D&D world (I'm building my campaigns inside Minecraft so I can present them visually to my players), this one was a ravine that I kind of got carried away with.....(the ravine sits below a castle I built)
What a wonderful idea! Although it might take a long time once you're not underground anymore...
Plus we'd all have to get +1 Picks of Diggy-Diggying
Well, if it's in creative peaceful mode you could use it just to show the layout? The hard part would be showing where the monsters are. The Neverwinter Nights engine (Aurora?) would probably work better.