"I wonder if I could strip the backpad and other weight reduction ideas to the Jam."
Hey John, if im reading this correctly, you're wondering if you can take out the foam pad inside the jam, and youre also looking for other things to strip off?
The foam pad is def removable, but it provides structure to the pack...even if its not that substantial to begin with. Without the foam pad provided, or at least some other foam pad in place (perhaps one that you would sleep on anyways), the pack will not carry that well. The jam is pretty sparse on features as it is. You can strip weight if you cut trim the side compression straps. However, you will lose the ability of them to connect across the front of the pack. Right now they are long enough to do that. This applies only to the 2009 version. The 2008 version has side compression straps that are shorter, and with buckles that do not mate across the front. You could remove the ice axe loops and retainers on both the 08 and 09 version. I've heard some people tearing off the front pocket altogether off their jams. The hydration sleeve is an ounce in itself, and removable without much loss of functionality. If you think that you will be using the entire width volume of the jam, then you can remove the "compaktor" (or whatever the system is called) clips and loops for a wee bit of savings. You could always trim the shoulder straps, and waist belt straps to fit your body. The strap that lashes across the roll top can be trimmed if you don't ever think you'll need the extra height volume that the roll top provides. In which case you could probably even trim out the roll top, or replace with lighter silnylon if youre into DIY
Most of the weight gain from the 08 to the 09 jams comes from the addition of hipbelt pockets, which are very usable imo, and the mesh backpad. The mesh backpad is the heaviest addition, and not that functional in my opinion. However, you can't really strip this off. Theres only a very thin layer of fabric underneath the mesh, and its definitely not dyneema. So if you removed the mesh, you would risk exposing a very thin part of the pack, compromising long term durability. The 2008 has no mesh on its back, and instead just has a backpanel made of normal dyneema like the rest of the pack, so durability isnt an issue.
I guess if you're dead set on a jam, you have to make the decision of whether its worth it to get the 09 for the pockets, but also bear the burden of a heavier mesh backpanel. Again the 08 has the lighter dyneema backpanel, but no pockets. You might be able to remedy with after market pockets, but i'm not sure about compatibility issues. Like Dan mentioned, take a good look at the MLD burn, Its heavier than the Murmur, but I think it makes up for it in features and durability.