We already have a feature to add locations from Digital Globe. Ideally, this feature would compliment that. A user could add their own high resolution, georeferenced orthographic image to build models on so that the exported model.kmz would be as geographically accurate as the user was capable of producing. An extension or feature to allow uploads of geotiffs or .sids would make SketchUp more GIS friendly and would cut down on the workflow time of building geographically accurate models.
There is also currently an option to include terrain data on imported Digital Globe imagery which should remain an option. However, some users have their own terrain data from another/their own source. There should also be an option to load in a georeferenced .dem to pair with your imagery.