Default profile with Active Directory
Have you looked into creating a local user template? Here for example: http://gigaom.com/apple/how-to-create-a-custom-user-template-in-snow-leopard/

The template folder is copied to the new user folder at first login. The problem now is how to deploy that user template to every new mac, but that's easily solved by other means (you can create a package and distribute it via ARD/munki/Casper, you can use puppet - which you should do anyway).

Mind you that every change to the User template will only affect new users; existing users have to be managed by other ways too (MCX via augmented AD schema, for example, is what we use).