This is very cool, and something I have thought about. How cool would it be to have Risk like boards but of different maps, like the US or Europe? Well Havoc has done that. Its a kick starter project but they have 15 designed maps so far, Civil War US, New York, United Kingdom, Los Angles, San Francisco, etc.. So far, all us Cities, sans UK and the solar system.
The maps look really nice! True to the RISK design framework. If you are at all interested in seeing to come to reality, head over the kickstarter page and give them your support!
Check out the Vid below