at one time I was looking for the same thing (a centralized database of route maps), and as far as I know there is nothing.

I wanted to try to make an online (web based) dynamic route-map generator based on the databases from the people at www.goldenware.com (the people who publish many of the airlines' online timetables), but they were totally not co-operative (I needed to get the structure of their database files).

If anybody out there has any contacts with the goldenware people and can help, please let me know. I still think it would be cool...