Mortgages that allow buyers to make low downpayments are making a quiet comeback, according to a recent analysis from Deutsche Bank. But do they have the staying power? So far, seven lenders have partnered with Fannie Mae and Freddie Mac in special programs to offer loans requiring anywhere from no money down to 3 percent down. Although the government-sponsored enterprises cap their high loan-to-value product at 97 percent, some lenders step in and subsidize the extra funds needed to make up the difference. The GSEs began...