SummitPost.org

possibly

Here is a couple. Certainly not like the volcanoes around Mexico City. Nonetheless it looks like an interesting area.

http://www.summitpost.org/mountain/rock/150367/las-nieves.html

http://www.summitpost.org/mountain/rock/150366/la-viga.html

Baja has a nice range called Sierra de San Pedro Mártir http://www.oceanoasis.org/fieldguide/sanpedromartir.html its highest peak is El Picacho del Diablo at 3100 meters. Here is Bob Burd's trip report http://www.snwburd.com/bob/trip_reports/picacho_del_diablo_1.html

Depends how high is high. If high is greater than 20k, then south of Denali, there are no high mountains until South America.

I second Picacho del Diablo as a very worthy peak. It is a beautiful mountain isolated in a very rugged range. It is well worth a visit (or two). Totally unexpected to see pine forests and snow in baja. On my visit, we saw a mountain lion about 40 meters to the side of the road pacing my car. It followed us for about a minute before it got bored.