I think an interesting application of SL would be to prototype developments and allow for people in RL communities an opportunity to real time do walk throughs of the developments.
Basically, as a land developer, you'd hire one of the SIM developer companies and they would build out the sim according to your development proposal.
Town councils and community participants would be able to log on and do a walk through to check out the development in an immersive, virtual environment.
I think some white labelling will be needed to make this happen, as well as a certain degree of simplifying the interface. It will, I have to admit, also move away from the one-shard approach, but given the number of developments (100s of thousands) that are happening around the world at any given time, I could imagine 10s of thousands of these simulators to be used.
I think Google Earth is moving in this direction as well:
http://news.com.com/Google+Earth+zooms+in/2100-1032_3-6082960.html?tag=nefd.lede