Welcome back A.R. Yup, I remember you. Well, the only way I know of to achieve the kind of effect with mountains that you are describing is to create randomly generated cloud patterns and then copy and paste them where you want them to go. I describe this process in my Eriond tutorial (see my sig) but that tutorial is directed at a more photo-realistic style map. However, you could use the method I described to generate and place the cloud/mountain structures, and then create a gradient map of them (again, I detail this in the tutorial), and just used this to represent terrain. Others may have better ideas, I don't know, haven't really attempted the style you are going for.
Cheers,
-Arsheesh