I am also a size 12...or actually, a size 10/12 in tops and dresses, and a loose 14 in the hips currently. (I am a pear shape.) I just bought some new dresses that are fitted through the torso and loose in the lower body, and they are size mediums...I haven't worn a medium in forever!!!
I wear LTM jeans, which are currently a size 12/14. (Specially cut to a 12 waist and 14 hip).