Justin O'Beirne of Latitude41, who created the awesome Examples of Styled Maps Using Google Maps API Version 3, has been at it again and has now created Additional Examples of Styled Maps Using Google Maps API V3. The new styles include a few examples mimicking the styles of other online map providers.
I've used Justin's example of copying the style of Bing Maps to try and reproduce the Bing Maps home page. It would be possible to make this look more authentic by emulating the Bing Maps zoom control using the Custom Controls function in the Google Maps API. However I've spent far too many hours on this already - so it's not going to happen.