Jeff, I did the JMT in 9.5 days. I don't hike particularly fast (average 2 mph) but I put in a lot of hours on the trail. I think my pack weighed an average of about 19 pounds without water. Of course that fluctuated depending on the number of days of food I needed to carry. My base weight was probably 9-10 pounds with requisite food canister. I have since been able to reduce that base weight w/o a canister to around five to six pounds. I was able to hike the Wonderland trail this summer with a base weight just slightly less than 6 pounds.
You can read my JMT journal and see what gear I carried at: http://www.trailjournals.com/idahomtman/. I now carry a 16 ounce sleeping bag (Montbell), 3.5 ounce pad (Gossamer Gear), 15-20 ounce backpack (ULA Amp or Conduit) and either a MLD Patrol Tarp or BD OneShot tent. There is also a link to my Wonderland trip and you can see the difference in gear carried. I brought the OneShot because of the typical weather on Mt. Rainier, but if I hike the JMT again, I will definitely go with the tarp.
