Frameless Packs: Avoiding the tube with straps?

Sometimes saving that last 1lb possible, is not smart.

Does a 7 lb baseweight really have much advantage over a 8 lb?

Not if its less comfortable overall, and doesnt carry heavy food loads well.

I noticed an Exped 60 got somewhat round when pack but this was not a problem because of the hipbelt and internal frame.

I think one problem is that most packs have the hipbelts sewn onto the sides. If the hipbelt was sewn on close to the center if would wrap around your hips better and the exact shape of the pack would be a bit less important. Hope this makes sense, I have some ideas I'll try to post later but to do them justice I need to draw some diagrams and right now I'm tired. Brian I'll try to let you know if I start a thread with my ideas.

I have done this a variety of ways. All are inserted in a sleeve sewn to the pack.
I have used flat aluminum bar stock – 1" x 1/8"; I have used solid aluminum rod – 1/4" diameter; and I have used a section of a 7000 series alloy tent pole – around 3/8" diameter. The rod stock I bent at the ends to wrap around the corner from front to sides, the others just stop at that point and are straight.