It's unusual to find actual 1940s-vintage shoes that you can dance in: if you can find them at all, they are either too small and narrow (people had smaller feet back then), or the leather is so old and brittle that it will crack and break if you try to dance in them.

So, I am recommmending Bleyer dance shoes. Bleyers are some of the best dance shoes in the world--they were created with dancing in mind. The uppers are wonderfully soft leather that feels broken-in the first time you wear them, and the soles are not too slippery but not too grippy. You can buy Bleyers from DanceStore.com.

If you want a local shoe source, you might try Mountain Gymnastics on Stuart Street, or The Dance Closet on Laurel.