When shopping ladies, do not limit yourself entirely to the women's sections. I stumble across great finds in menswear. Great for the slouch, comfortably oversized look. Here's an example of something I came across at H&M today.
Grandpa-style sweater. On the hanger
On the male mannequin.
And finally, on me.
(This picture makes my legs look really short :P)
If you have extra time, browse the men's section a bit and see what you can find!