Hi everybody,
By accident, I've found that very nice map tool called Geoportal.de. Unfortunatly only available for Germany. It offers very detailed basic maps including house numbers.
Have a look right here:
http://www.geoportal.de/DE/Geoportal/Karten/karten.html?lang=de&bbox=-172930.866317,5292886.371891,1372930.866317,6007113.628109&background=hintergrundkarte
You can choose from different open source WMS services to add to the map and export it to a kml file.
Have fun with it. 8)
Cheers,
berkley