There's a style available for Campaign Cartographer 3 that simulates those maps quite well. http://www.profantasy.com/annual/2009/february09.html
That will require CC3 and Volume 3 of the Cartographer's Annual.
It's also possible to make mountains like those with a technique similar to the caterpillar brushes shown here: http://www.cartographersguild.com/sh...ht=caterpillar