In Mexico many people do tend to "middle" names, altho whether they're considered as "middle" or not I don't know (they could be confirmation names, etc.). Some of the folks we deal with in our organization down there are distinguished first-name-wise as "Juan Pablo
", "Juan Diego
", etc., rather than by any use of their last names/
The two last names thing is used in Mexico as well as (I guess) in other Hispanic cultures. Many people make no day-to-day reference to the final (mother's) last name in business dealings, but Veronica Juanita
Gomez Gutierrez (unmarried) might properly sign her name in a business context "Veronica
J. Gomez G."