You might want to look at the Klymit air mattresses to shave off a few more ounces--I have a full length Inertia 72 x 1.75" with pillow (separate inflation) and it comes to 12.5 oz and rolls up to about the size of a 20 oz coffee. They also have some 3/4 length pads that weigh 7 oz and roll up to about the size of a soda can: http://www.campmor.com/outdoor/gear/Product___98096 The clymb also has some really good deals on these.

Ooh, ooh! I got a 40 F 600 fill down Lafuma TMB sleeping bag for $80 at the Clymb with free shipping. (2 lbs, 4 oz, compresses to size of soccer ball with included compression sack, also comes with storage bag) I tested on a night when it it went down to 36 F here in Santee, and was fully comfortable, wearing basketball shorts, thermal long sleeve jersey, leg warmers, & socks. using the bag as a quilt on top of the above Klymit air mattress. You could knock 9 oz off from your Mountainsmith bag. A great deal for any tourist.

Disclaimer: The Clymb requires free registration, just like these forums. It seems they use it just to send ads to your email, like Campmor, Amazon, and every other place does.
If you register from my invite here:
http://www.theclymb.com/invite-from/stevepassert
they say they'll credit me S25 toward future purchases, but it's OK by me if you don't want to...it just makes a little baby kitten cry every time you bypass it.