This DEM file has not changed since 2010 that's why it does not get shared every update ,obviously terrain does not change that much.
Header: 16.09.2010 15:47:29, DSKIMG, XOR 00, V 20.11, Ms 0, D224800BG000Mapset: North America DEM
fat: 1000h - 1200h - 24000h, block 16384
maps: 144, sub-files 144
Available here