@Kalle_H: Unfortunately, there are no tools that automatically optimize a model by removing all geometry that isn’t visible. The developers of LEGO Universe wrote scripts in Maya to do that, but I’ve managed to look at the actual models using NifSkope, at tool normally used for modding Fallout 3 (both games used the same engine). However, I don’t have the time to make those tools, or any money to buy them if they even existed.
@KVogler: Most models are static and unbreakable, especially the larger models such as buildings. There are times when models would be built or smashed during gameplay, but those are typically small and simple, such as cars or containers. It is likely that some larger buildings will be destroyed or built in realtime during gameplay or cutscenes, but that would be very localized.
Also, my current workflow is that all models are made entirely in Max, then exported as a single static mesh to the engine. At first, the entire model is made using the bricks from my library. Once finished, I plan to create LODs by replacing every brick with their optimized LODs. Most bricks that will never be completely visible will just be a convex shape without studs or interio, so a 1x1 brick is just a box (in most cases, the studs and interior contain the most triangles as they are cylindrical). But the outer edges are beveled/chamfered with custom normals so every brick stands out when stacked together. The lowest LOD will then be the same but without the rounded edges.
I’ll try to show some pictures of the LODs later on, and possibly a simple example of a model.