Meet Mortimer L. Downey, 72. Downey and his rockin’ beard will reportedly be one of the four new federally-mandated appointees nominated to WMATA’s board of directors by the Obama administration. Metro’s new-look board will certainly have a lot to deal with, including an uphill search for a new general manager, potential service cuts and a budget in tatters. But Downey, a consultant who previously served in the Clinton administration and as executive director of…