Per accident (err, youtube's related video suggestions) I stumbled upon videos from the fine folks of UC Berkeley - they're doing some pretty cool stuff actually. On their grid of 40 Opensim servers and in SL.
Like Ortho-Mapping for example. In other words: mapping orthoimagery (aerial views, in this case of the earth) onto terrain.
Watch the videos below to get a bird's view of the Berkeley area:
From the text going with the second video:
Real-life geographic information is modeled at three levels, or scales of detail. The (1:42) Level 1 build mimics Google Earth with globe-type data at 1/42 scale. The (1:16) Level 2 build adds LiDAR first-return data to include the tops of every building and trees at 1/16 scale. The (1:3) Level 3 build is the best we can do, solid geometry 3D graphic primitives and real-world textures hand-tuned for optimal streaming at 1/3 scale."Mimicking" being a bit of an understatement in this case, ha! I can see Earth Grid fed with real time real life data before me already.