Depends on whether the owner of said high quality map database will license it for inclusion in OSM. My understanding, from following the Australian OSM mailin

Depends on whether the owner of said high quality map database will license it for inclusion in OSM. My understanding, from following the Australian OSM mailing list, is that it takes an individual to pursue this with a government agency, which is a ton of work, and often you'll just get a 'no'.