I love knitted dresses from the 1940s - although I think the amount of time it would take to make one would drive me nuts!
But if I was going to make one, it would probably be this design. Smart and tailored, with an amazing leaf design down the front bodice and pleated skirt. From Sun-Glo Series 86 - Young Styles for the Larger Figure.
This design requires fingering weight yarn, knitted on 3.25mm needles.