Just when I thought I had pinpointed the origin of the civilian mess jacket to about 1930 I stumbled across a period reference dating back to the turn of the century. The following passage is from The Blue Book of Etiquette for Men, copyright 1904:
There is need of a costume for evening dress in hot weather which will be cooler and more comfortable than our present attire. We cannot look to England for a suggestion, because the same condition as to climate does not there exist, but the example of Englishmen in the Colonies may be worth considering. Several years ago, the writer endeavored to introduce the East Indian hot-weather costume. It obtained some vogue in Chicago and other cities, but failed to make a permanent settlement. The dress consists of white duck coat and trousers without waistcoat, the place of the last being taken by a white or cream-colored kummerbund, or silk sash, about a foot broad, which encircles the waist three or four times. The coat is cut on the lines of an Eton jacket, without any buttons. A stiff, white linen shirt and dress tie, patent leather pumps and silk hose, complete a costume exquisitely neat and fresh, combining formality and ease in happy degrees.
If the author lived long enough to see his suggested outfit catch on like wildfire in the thirties he must have no doubt felt quite vindicated.