dulci - I believe Katie's jacket might be by the Row. Possibly their shirred leather jacket?
I'm sure RO goes down as low as 36 and while I believe the leather jackets perhaps fit particularly small, with my cardigan, it's really far too big. I have quite small shoulders and this probably exacerbates the issue but I have the roll the sleeves up about 5 - 6 inches so I would probably err on the side of caution and get a smaller size (esp. as leather will give a bit).