The name of that group is Son de Madera (The Sound of Wood). They make their own instruments. The big deep, 4-string base guitar is called a
guitaron (gee-tar-OHN). The 8- and 10-string rhythm guitars are called
jaranas (har-ON-as) and the funny looking cutaway that Ramon Gutierrez is playing is called a
guitarra de son and/or a
requinto jarocho (gee-TAR-uh day sohn)/(ray-KEEN-toe har-OH-cho).
Solo (Ramon with 5-string requinto electricfied):
http://www.youtube.com/watch?v=6znUza4t6gs 
Here's a 1-of-a-kind instrument, a variation on a Cuban Tres: A 9-string (in three courses) from Ramon's brother in Jalapa, Veracruz played by Hugo Arroyo of the California group
Los Cenzontles (The Mockingbirds).
http://www.youtube.com/watch?v=blMhqlxTKwc...and then the whole group:
http://www.youtube.com/watch?v=4b493gJuiuMThese people are ethnomusicologists, not just a street band. The (highly educated) chicano fellow playing lead with the big black guitar is a graduate of The San Francisco Conservatory of Music!

I find this kind of music from Veracruz somewhat more than soulful and addictive.

My goal...
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...is to live in a trailer.