NEED HELP WITH A GINGERBREAD MOUNTAIN!?

I am a professional baker, I have entered MANY Gingerbread house contests and have always missed the elusive BEST IN SHOW. Many 1st prizes, but I want that dang BIS! So, I need an idea or 2. I want to build a 4 foot tall mountain out of GB where all my mini houses and a train will sit as tho they were a mountain village. I can't seem to think of a way to do the MT. It will have a lot of weight on it, so It can't be just GB. Syyrofoam in that quantity would BREAK THE BANK! Anyone have an idea?