Kuanomar,

We keep these in our "mini kits", because I've found them to be very durable (I've watched videos of people boiling water in them - SERIOUSLY!):

http://www.cascadedesigns.com/platypus/handheld-hydration/platy-bottle/product

They also fold down to almost nothing.

The PlatyBottle can be used a "source reservoir" for a forced feed filtration system if you add a Frontier Pro filter.

http://aquamira.com/preparedness/frontier-pro-filter-system

Let me explain....

You can fill the Platypus 1L or 2L bag with untreated (but prefiltered) source water, and suspend it upside down from a tree/whatever with 550 Cord. The Frontier Pro filter screws on the Platy bag, and gravity flow filters water into your hydropack or bottle below. This allows other chores to be accomplished while refilling your main water source.

One last question - did you include a way to sharpen your knives?

Again - looks like a great start!