I don't think the licensing problem can be solved with money. TomTom owns the mapping data and obviously wouldn't let Google provide a navigation app since it would put them in direct competition with TomTom. That's why Google had to create their own maps for the US.
The map downloading model you're describing already exists and there are already plenty of other companies providing in-car GPS devices for that. I don't think it's appropriate to implement that sort of thing in a smartphone since the entire point is that it should always be connected.
The map downloading model you're describing already exists and there are already plenty of other companies providing in-car GPS devices for that. I don't think it's appropriate to implement that sort of thing in a smartphone since the entire point is that it should always be connected.