Para_Mars for Ickylevel's Parasite gamemode (http://forums.facepunchstudios.com/showthread.php?t=321663) is completed. It will be included in the next parasite update but you can download it here. I assume it would also work well for comic posing and small scale building as well.
This is a Parasite game mode map. It is a military/scientific base on Mars with many features. This map contains custom textures, High Dynamic Range lighting, a map icon, a 3-D skybox, and much more. There are 32 human and 32 alien spawns.
Credits to Ickylevel as well for his custom textures, and great game mode.