I got to rumbling around in my water bottle collection the other day and re-discovered a Nalgene hard plastic canteen that I think is an interesting option. It mimics the shape of military canteens used since WWII and it made of BPA-free Triton plastic, just like the common 32oz/1L Nalgene bottles. The surprise was that they weigh 4.6oz, which is the same as the HDPE bottles. The neck is like the other narrow neck Nalgene bottles.
They fit in all my packs with mesh water bottle pockets and are actually more secure. I like the handling ergonomics too. I'd like to see an UL waist pack made for one or two of these bottles with a pocket on the other side or back. There are all kinds of military style holders for this shape, but none are really in the UL realm.
