I like the second B&W image quite a bit(the first has too much black for my tastes). I would love to see just the line art for the last one though. It's hard to tell with the color, but personally I think you have hit on what I have been "trying" to get for quite a while, which is avoiding the cut off bottom effect. As Gidde noted, it's fairly easy to fall into a pyramidal approach(I admit to having done it several times) and while it can look ok in some maps, I think the "random" sawtooth approach works quite well. I even think if your careful, you could go "deeper"(relative to the base line of the mountain outlines) and still have it look very nice.