BEIJING/HONG KONG (Reuters) – For an economy facing its slowest economic growth in a quarter century, a 7.7 percent year-on-year rise in new home prices in December would seem to offer China some light at the end of the tunnel. Property prices were rising fast in mega cities like southern Shenzhen, where prices rocketed by nearly 47 percent, Shanghai, up a healthy 15.5 percent, and Beijing, which posted a respectable 8 percent gain over a year ago.