Does anyone have the game called American Conquest?
In it they used grayscale images of grass, sand, rocks on top of colored terrain to create realistic and 3D-looking terrain on a 2D map. They also had very many pictures of good looking trees rocks and plants.
(and its a great game by itself)
Look at the grass, sand, trees, and mountains in the screenshots:
http://www.americanconquest.de/screenshots/images/big/_inc_spa.jpg
http://www.americanconquest.de/screenshots/images/big/_spa_fra.jpg
http://www.americanconquest.de/screenshots/images/big/_britishlookout.jpg
http://www.americanconquest.de/fb_screenshots/images/big/_lmode.jpg
http://www.americanconquest.de/fb_screenshots/images/big/_rus_hai.jpg