Is there a general rule of thumb for optimizing / low-res meshing a model for mobile (max poly/vert count), for a scene where there would be several occurrences of the same? The target platform would be mobile device.
Which platform? Androids are very different. Even iPhones are different. For most of them overdraw (not the vertex count) is the issue. How many % of these vertices will be skinned? What kind of shaders are you going to use? How many texture slots? How many different materials?
Despite all these questions I tend to think about 50k static vertices in scene :) (and the scene is reasonable: not to much overdraw and not to many batched objects with shaders using not more than two textures).