The GSE loan limit, a contentious mortgage market issue in past years, will receive its biggest boost ever on Jan. 1 when the so-called conforming loan ceiling will rise to a hefty $417,000. The new limit, up a record high 16 percent from the current level of $359,650, was approved by the Office of Federal Housing Enterprise Oversight and is based on a monthly home price survey conducted by the Federal Housing Finance Board. The…