I have been making a few special pieces of my own for AA1914 to make the game more interesting. I designed two pieces so far; a truck and an FT-17 Renault tank model for the WWI game. You can find them here : http://www.shapeways.com/search?q=jsebt
I try to make them in their most affordable material since they are playing pieces, so they have a balance between detail and structural integrity.
If you are interested in trying something out, please let me know. I welcome some challenges !