"The foreclosure problems in small-town America may be even more widespread than in cities," the AP reports.   Reporter Evelyn Nieves travels to Merced, California, (map above) a Central Valley town that may have the highest concentration of foreclosures in the country.Nieves reports the foreclosure problem may be worse in rural areas than in the cities, because part of the problem is hidden. Mobile and prefab houses "make up at least 15 percent of the nation's rural housing, and three-quarters of them were financed with installment or personal property loans rather than mortgage loans," Nieves writes. And when these loans go bad, the property is simply repossessed — and the action is never counted as a foreclosure.Three Central Valley counties are near the top of the national foreclosure rankings: Merced, San Juaquin and Stanislaus. The No. 1 area for foreclosures in the Cape Coral/Fort Myers region of Florida.