"Americans' appetite for second homes in Mexico remains strong", says Carlos Garza, CEO of Texas-based INB Financial Corp., which started offering cross-border mortgages last year.

Evidence of the demand: Mexico's top bank, BBVA Bancomer has made about $115 million in loans to Americans and Canadians so far this year and has a full-year goal of $200 million. The average loan is about $500,000, says Isidoro Sanchez, a director of business development at BBVA Bancomer.

Most of BBVA's business has come from professionally active Americans, ages 40 to 55, who are looking for a weekend retreat, and from semi-retired buyers between the ages 55 and 60 who spend several months a year in Mexico, Sanchez says.

"Given the kind of homes that are being purchased – $800,000 to $2 million – this is a segment that is still buying even though there is a crisis in the U.S.," Sanchez says.

Mexico City-based real estate research firm Softec Consultoria Inmobiliaria predicts vacation-home sales to foreigners are set to reach 35,000 units worth $17 billion in 2012, up from 18,000 units sold for $6.4 billion last year.