Have you considered a .tel site? You could list all your various branches very easily.
Alternatively why not a .info site with a contact page that lists all office locations then you only have to change one page for all sites to be updated.
Personally my contact page lists 12 global offices as follows:
Country/Region Location E-mail Phone Fax WWW
This works extremely well for me, under location I only mention the city/town, not the full address.