It should be easy for a programmer.  You would just have to add a few database columns on the members table, then update the signup form and the profile management for logged in members.  You may also want to integrate an administrative function to lock accounts until you've reviewed new applicants.

To detect US vs Non-US you would get a copy of the Maxmind GeoIP database and use that in the signup code to determine location by IP address.

Cheers.