I'm very interested in using the Maps extension, but I'd like to overlay a vector layer, e.g. to show the extents of a park, city, etc. Has anyone considered adding such support to the extension? I'm also interested in a lightweight alternative to OpenLayers, namely Leaflet [0]. Also check out the new Leaflet Vector Layers [1].
I suppose the biggest question is where should the vector data come from. For simple polygons with a few dozen points it could be passed in directly. With Vector Layers you can pull data from GeoCommons [2] and other databases easily.
-Josh
[0]: http://leaflet.cloudmade.com/ [1]: http://geojason.info/leaflet-vector-layers/ [2]: http://geocommons.com/