I recently finished making some hills and mountains using a different type of plaster than the scupltamold stuff that you suggested. I wonder if the stuff you used is lighter than the stuff I used. The stuff I made was not quite diorama quality as I built them for my wargame table, but anyway here's a picture of some of my work on this site:

http://www.joedios.com/dioramas/sho...58&goto=next&c=

I also put up a how-to section of how I made the various scenery pieces on my site http://thewayofwar.net/how-to

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I have a new site for my table top tactical strategy role playing game for action figures and miniatures. There's also diostories there too! Check it out at: http://thewayofwar.net/