Having agreed to pay billions of dollars in damages for underwriting allegedly faulty FHA mortgages, the nation’s megabanks could be pondering a better idea: Creating a portfolio product that accomplishes the same task as a low-downpayment, government-backed loan. According to industry officials who claim to have knowledge of the situation, Wells Fargo and at least one other top-five ranked lender are working on such a concept, but it remains to be seen whether they will ever get there, and if they do, whether such a creation can amass any type of volume. When asked whether Wells was working on an FHA-like portfolio loan, a spokesman did not dismiss...