Extended / dependent drop-down list for sign-up?

##I’m looking for something like this:

Otherwise, I won’t read such gigantic list, to provide additional information of myself as a new user.

Another – better way – would be, to work with conditional drop-down lists: The first choice inside the first field would limit the entries to the relevant ones at the second field.

Is something like that possible for customized user fields?

Thank yo all in advance