I found this hydration pack at my local wal-mart.. It is great for carrying stuff and up to two liters of fluid.. I keep my extra plugs plug tools light jacket and a couple other misc tools in it... The picture is one with it slap full mine is less than half that big.. It has very padded straps ,a chest strap and a waist strap to keep it in place I did not even notice mine after a day of riding..
http://www.walmart.com/catalog/product.do?product_id=8187853
