Hard to beat the issue canteen cup (folding wire handles, not the old VietNam & earlier era type with the L shaped folding handle). Similar in style and volume is the stainless steel cup that nestles on the outside of a Nalgene bottle. But larger kettles take up no more room... in anything larger than my ready pack, I continue to carry and use a battered and blackened aluminum 2 quart kettle with a bail and tight lid. A stuff sack sits inside the kettle and is full of... things. The kettle essentialy takes up no room.