The Google Maps team has officially announced some very cool new added detail to certain large cities when in the standard “Map” view. However, the new detail isn’t (yet) available through their API, so tough luck for your lovely mashups. No map-detail love for Orlando either, though the old homestead in Miami got some.
For my two cents, Google should instead focus on implementing a variation of their relatively new polygon feature so that users can create meaningful linear information, such as outlining bike trails and defining boundaries. Adding all those layers into the main map data will just make Google Maps even slower than it already is!