Check out your local public library for a book in the series called "Dover Everyday Fashions" for 1940s. It's basically reprinted pages from old Sears catalogues for each decade since the 1900s. There are several 1940s suits from the war period and post-war period, and it shows how the style changed. (The prices are a hoot -- $2.99 for shoes, etc.). I currently have them out and am renewing them from my local library.
Also, for fun, check out: Glamour Daze -- a great vintage website.
http://glamourdaze.blogspot.co.....-code.html
http://glamourdaze.blogspot.co.....-late.html
http://glamourdaze.blogspot.co.....ow-to.html
http://glamourdaze.blogspot.co.....drobe.html
http://glamourdaze.blogspot.co.....drobe.html
>> "The color of fashion in the early 1940's went to war as well, with patriotic nautical themes and dark greens and khakis dominating the color palates, though some morning dresses had bright floral shades.
After the war, colour became a feature once more, with shocking feminine primary colors becoming the rage, as exemplified by the glossy Vogue Covers."
It is possible to find a modern suit and tweak it slightly to have a 1940s style: just look for a shorter to hip-length jacket that is slender cut with slightly larger shoulders (but not 80s shoulders, that would be way too big), and a slim a-line skirt. I have a suit I bought a few years ago that has a slight 40s vibe, especially with the right accessories.