I'm 5' tall, living in Michigan and frequently have to be outside for recess as a subsitute teacher. My coat: The North Face metropolis. It's supposed to be 3/4 length, but functions as a knee length on me. The sleeves can be turned up too (I have short arms). This coat is very warm for this climate and not too puffy and works nicely over tunic tops.
I've had it for several years and it still looks good. You can wash and dry it(with tennis balls in the dryer for the down)at home. By the way, as a 600 fill down coat, it works in 40 degree weather, as well as -10 degrees!