Today there was a post on Searchengineland along a similar vein, it was about outdoor advertising which can be integrated into Google maps (online).
The one I found the most intriguing was where Google Maps could replace the content on billboards (for example in Times Square), with new ' virtual ads' in its streetview. Apparently, Google has already been granted a patent to do this (although the link in that story doesn't go the relevant patent).
Other ideas for getting advertising in Google Maps was to use land advertising (e.g. huge sand impressions), sky writing, rooftop advertising or even sponsoring a town to rename their town to your brand name! (crazy).
I have one to add to their story though - how about your fleet vehicles? If you knew where Google car was going to be, wouldn't you place your fleet vehicles there? E.g. like how I Google Street Viewed Covent Garden, and I got this:
This kind of Google Maps advertising wouldn't be suitable for all Google advertisers obviously. It would be suitable for those advertisers who want more branding opportunities - and due to the fact that maybe your customers aren't necessarily using Google Street View - I think you would have to do it hand in hand with some quirky PR campaigns.
