The Berghaus Yeti's are pretty specialist but they are great for snow use and extremely muddy conditions. They are however, quite expensive, I ended up with the British Army DPM versions for 1/6 the price.
http://www.militarymart.co.uk/index.php?_a=product&product_id=1906It pays to shop around!
Even today I was in my local Outdoor equipment specialist shop. I came across a £25 North Face Base Camp Travel Canister bag.
http://www.thenorthface.co.uk/tnf-uk-en/base-camp-travel-canister/p52330.html(essentially a Toiletries bag), which was interesting because I had purchased an identical bag (without the TNF Branding) a few days ago for the BOB project.
http://www.fieldandtrek.com/karrimor-wash-bag-784006