As home prices skyrocket, so does the size of down payments. Buyers from Boise or Bethesda are feeling the squeeze as they stockpile down payments that often exceed $50,000. Those who are struggling include middle-class families earning anywhere from the national median income of $89,000 to $100,000 or more. They face a particular dilemma. They earn too much for traditional down payment aid — but not enough to qualify for a mortgage without a big down payment. But there’s financial relief in sight for ...