I took all the postcode sectors for the UK and created this KMZ file.
The accuracy at the street level leaves something to be desired.
If I could find any interesting post code sector data, I would be interested in creating a thematic map. Anything with counts and/or dates.

Here is a real estate example. Use your imagination to estimate what the count represents.

I tried adding the file here but it won't take it. So here it is with the google earth API with a link to download the KMZ on it:
UK Postcode Sectors in Google Earth API with link to download the KMZ file