Many here are familiar with the excellent Alok-Saks. They now are producing 6"x9" models with pleated bottoms, which greatly increases their utility. These bombproof bags are great for packing many types of survival and medical gear. This is the link I found, there may be other sources:

http://www.backpackinglight.com/cgi-bin/backpackinglight/aloksak_op_sak_9x7.html