Extra Small Tall

Where are you shopping for extra small tall clothes? Specifically dresses. My 14 year old is 5'10 & 100 lbs. We need clothes that are typically a zero or two tall. We've had some luck with American Tall pants, but there's not a lot of dress options. Seems like Gap, Long Tall Sally, Lands End, etc. start tall sizes around 6 or 8.