I'm 'only' 5'7 too and also plus size, and I find long sleeves on QVC fashion are made for orangutans, whereas 3/4 fit ok. I remember the Join fashion range and I always bought the cropped trousers because they would fit just right for me, just above the ankle. So its horses for courses and body shape.
I always have to laugh at those articles in magazines where women have lost weight and dropped down 10 dress sizes. They nearly always start off at a size 22 the size I am, BUT to me those 'before' photos look like they're a size 28 or 30, and I think no way would they fit into a size 22. Usually they have very chubby faces - where as I don't, a lot have quite sturdy legs, again my legs are slender, so my size '22' is the bit between my shoulders and my hips. Horses for courses.