well to keep the game running smoothly you are able to implement your own LOD systems. A number of tutorials and code has been posted on the AUM i think.
If you're a pro user then i'm sure LOD is already automatically enabled in the pro version. The poly limit is not a final definite number and i would guess that it is limited to your hardware rather than the engine itself. Although i do belive DirectX has a limit on the number of polys it can render, somewhere around 65000 i recall. Please correct me if i'm wrong.
As for back-face culling then yes A7 does support this.
Here is a section from the manual about the render engine...
"The engine determines which of the potentially visible objects are within the view frustrum. The view frustum is the area in front of the camera which the player can see.
Anything completely outside of this area cannot be seen by the player. The view frustrum looks like a pyramid with the top chopped off.
Any object remaining in the view frustrum is really rendered by the engine. This includes objects that are only partially inside the frustrum (otherwise you would see them 'pop' at the far clipping range), and even polygons facing away from the camera (backface culling)."
For more info type in "render" in the manual or visit here >
http://www.conitec.com/beta/culling.htm
