A growing number of the people whose homes are in foreclosure are refusing to slink away in shame. They are fashioning a sort of homemade mortgage modification, one that brings their payments all the way down to zero. They use the money they save to get back on their feet or just get by.“Instead of the house dragging us down, it’s become a life raft,” said Mr. Pemberton, who stopped paying the mortgage on their house here last summer. “It’s really been a blessing.”This type of modification does not beg for a lender’s permission but is delivered as an ultimatum: Force me out if you can. Any moral qualms are overshadowed by a conviction that the banks created the crisis by snookering homeowners with loans that got them in over their heads.