C
Sorry, it's been a crazy week and I haven't been keeping up with the thread.
VE lets you overlay a number of shapes on the map: simple "pushpins" for points, polylines (like for roads), and polygons. Polygons can have fill colors, edge colors, and variable opacity.
It can get a little slow when it comes to displaying a lot of polygons, so if you want to have more than, say, 100 of them on the map at once, you have to be tricky about it; but there are ways.
For what you're talking about, you'll probably want more than a simple KML file. You'll want a back end web service of some description that can serve out polygon & business data, then the web page can interact with that service in an ajaxy manner.
Creating the polygon is pretty easy. Here's some sample code from the interactive SDK:
var ll = map.GetCenter(); var lat = ll.Latitude; var lon = ll.Longitude; var shape = new VEShape(VEShapeType.Polygon, [new VELatLong(lat,lon-0.15), new VELatLong(lat+0.1,lon-0.05), new VELatLong(lat+0.1,lon+0.05), new VELatLong(lat,lon+0.15), new VELatLong(lat-0.1,lon+0.05), new VELatLong(lat-0.1,lon-0.05)]); shape.SetTitle('My polygon'); map.AddShape(shape);
So, imagine that in a loop, going over the data that is returned by the service and you've got the (very) basics of it.
I can probably send you a (static) example, if you want to private-message me your email. I'll need to strip out the client info, but you'll be able to see how the data is brought in (I just use JSON), and how VE renders it.
Hope that helps a bit.
-cw