MEXICO CITY — Crippled Detroit automakers have received limited financial aid from Washington, Ottawa and even Stockholm. But have they also considered the possibility of asking Mexico City for some assistance? The numbers suggest it could make good economic sense on both sides, particularly now that the Detroit Three are building more cars and trucks in Mexico than in Canada, industry watchers here are noting.Mexico surpassed Canada for the first time in October in cumulative vehicle production. Through December 29, Automotive News reported, total vehicle production in Mexico climbed 3.5 percent to 2,161,725 units, while total vehicle production in Canada plunged 18.9 percent to 2,082,303 units.Mexico's growth is due largely to the strength of Volkswagen there. But the Detroit Three have a significant presence as well, having built 1,098,560 vehicles in Mexico in 2008, or more than half of the country's total production.In that light, General Motors, Ford and Chrysler may want to seriously consider passing the hat in Mexico City to raise a little more cash. Mexico's Central Bank has treasury reserves of about $90 billion, so a loan equal to the one approved by Canada for Chrysler and GM of around $3 billon shouldn't harm the country's economy.It would also be a way to show the Mexican government's continued support of the North American auto industry.Inside Line says: More funding alternatives to support the survival of Detroit automakers. — Loriana Marietta, Correspondent