This week, 127 mortgage banking executives attached their names to an open letter to members of Congress, urging federally elected politicians not to cede the work of housing-finance reform to the White House and the institutions it controls.The correspondence asks lawmakers to back draft legislation that creates a new “guarantor-based” system that builds on the current infrastructure created and maintained by Fannie Mae and Freddie Mac.The executives, members of the Mortgage Bankers Association, favor improving the system by having “two or more” guarantors. The group believes a guarantor-based system – as opposed to an “issuer-based” system – is the best way to meet the nation’s housing-finance needs.