Just saw this one months later. I'm 5'3", so on the tall side of petite, and I usually have to take at least 6" from the (total--about ½ from the top and ½ from the bottom) length of patterns (at least the Big 4). Given that, tell me they're not designed for model-tall women--not realistically, average-sized women. That said, since you're even smaller, I wonder if it would be easier to adjust the width of children's sizes if you can find any in the styles you like (or at least use them to make appropriately-proportioned slopers to adjust the adult styles you like). Don't know if that would work--maybe the proportions are all wrong for that.
Vanessa, mother to James (36), Sarah (34), Aaron (32), Adam (29) and David (26)