...but I say it first, it didn't work in game.
But i want to share it anyway. I was searching the web for something what could be useful or bring back some performance when working with additional meshes (3d grass, Speedtree Zones). I found some scripts which looked very promising and even worked in Unity. But yes, it has somehow its hands on the Main Camera (only had to rename the "Main Camera" to "Player" to make it work btw). In these scripts is only one value you can edit, how far away from the player an object gets turned off/on. It worked succesfully (again, only in Unity) with my clubhouse and non-splitted 3d grass meshes for example. The distance value counts from player to center of object. So probably larger meshes would have needed to be splitted and the parts kept as single objects to keep the scripts value low.
Maybe completely useless to show it but something like this could be useful especially for the shorter 3d grass which is only needed not too far around the player. How much of a performance gain this actually would bring in game i don't know. Maybe MJ can make an exception and allow these scripts to be working in game or make some secret tests and tell us... 
Here is a link to the video if you're interested. (Don't know how or if i should embed it..)
Edit: Ah, got automatically embedded...
