@ Slin:
Maybe, you can use something like "Mysty Mood" and/or "Seed it!" in combination with the weeds and trees of Loopix to achieve a huge and appealing and fast rendering landscape.

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt