Framing lumber prices in US spiraled downward, as mills searched for trading levels to little avail. Deep double-digit cuts left traders all the more uncertain about where a bottom might be found.  Futures helped set the tone for the rout, as two down-limit days threw cold water on a modest rally on the board Tuesday. The Random Lengths Framing Lumber Composite Price fell for an eighth straight week. The $28 drop for the week pushed the index to its lowest level since January, and $120 off its record high set in June.     ...