Which designer is most associated with Carole Lombard? I believe most movie buffs would reply, "Travis Banton." Nothing against Irene or several others, but Banton earned her trust early on at Paramount -- so much so that when Carole was loaned out to other studios, more often than not Travis would handle designing chores. (Think "My Man Godfrey" at Universal, for instance.)
This gown he designed for her is proof:
It was described as a "blue lace minaret silhouette over a draped satin slip," and was designed for Lombard to wear at a ball in New York City. Since I believe Carole's final visit to New York came in early 1935, I'm not sure she ever presented herself in it to New Yorkers. Here's another photo of her in the outfit:
The gown was modeled by Jeanette Warren at a fashion show sponsored by the Los Angeles Times, which in its Feb. 29, 1936 issue showed her wearing a slightly modified version.
Note the only significant difference was the size of the collar. It worked wonderfully for both ladies, and proved once again Banton's amazing still at creating a wardrobe.