I was playing with the worldgen a bit and came up with a decent world, thought I'd give myself a challenge in it and do an above-ground fort in the woods, Robin Hood style. I even gave my guys archery skill and planned on setting up a trade depot away from the main camp and stealing from all the traders who came through.
I settled in a forest by the junction of a winding river. I made a huge area to play in, since I figured I'd be entirely above-ground and there wouldn't be nearly as much stuff to hog my CPU as there normally is. There was an aquifer, but I figured I'd just collapse some soil into it and dig through if I needed stone.
Preparations painstakingly made, I embarked to discover this:
http://mkv25.net/dfma/map-3158-charmglenGiven the type of area, I never expected extreme cliffs - forgot that I set the elevation X- and Y-variance to 1600! The cliffs are so steep I can't even believe it. Theres a 13-story waterfall in one spot. My guys embarked a full 28 levels above the bottom of the map (on an isolated little island in the sky, no less). I spent a half hour or so looking over the map and never even got around to trying to play it. Given the circumstances, I think the map will run too slowly anyway.
If anyone's interested, I can provide a seed and mapgen specs and location and whatnot. This is just so many kinds of awesome I don't even know how to handle it.