Re: 737NG emergency descent procedure...
Just in case you have not got acess to the latest FCTM (Backtrack, not all operators issue it to their crews or reissue the updates), here is the extract. This section was changed on the 3-900 series FCTM on 31 Oct 05.
"Landing Gear Extended Descent
The rapid descent is normally made with the landing gear up. However, when structural integrity is in doubt and airspeed must be limited, extension of the landing gear may provide a more satisfactory rate of descent.
If the landing gear is to be used during the descent, comply with the landing gear placard speeds."