I am a HUGE fan of classic films, and a sucker for romantic ones. I was wondering if anyone has written books in that style, especially (but not limited to) being set in the 1930-1950's time period? Some of my favorites are "It Happened One Night", "My Man Godfrey", really anything with Cary Grant especially "His Girl Friday", "The Philadelphia Story" and "Holiday". The Preston Sturges romantic comedies- "The Lady Eve", "Sullivan's Travels", "The Palm Beach Story" etc  and Lubitsch- "Trouble in Paradise",  "The Shop Around the Corner" etc. Even some Doris Day/Rock Hudson-esque ones could be cute :) Also, would it be too much to ask if there are any like one of my all-time favorite re-watches, "Mrs. Miniver"? Thanks in advance!

Well, you could read _Mrs. Miniver_. :-) Very good book, though not really all that romantic.

I think Loretta's Chase's books have a romantic comedy feel to them, though they are set in the Regency.

For a screwball comedy (reminiscent of the Doris Day/Rock Hudson-loved Lover Come Back) I would recommend Jennifer Crusies Faking It.  It is a contemp but has that banter feel to it.

You could try Dorothy Garlock's books. She writes a few set in the 1930-40's, Great Depression and WW2 eras.