Primitive Christianity Revived, Again
You might find the book Quaker Aesthetics, ed. by Lapsansky and Verplanck, of interest.
You could look at Amelia Mott Gummere, *The Quaker: A Study in Costume*. The author is prejudiced against plainness, so one would have to keep that in mind.
Also, see Stephen Scott, *Why Do They Dress That Way*, a more balanced treatment that covers the full range of plain Christian traditions.
You should also look at Melvin Gingerich, *Mennonite Attire Through Four Centuries*. Gingerich also has an anti-plain ax to grind, but his work is nevertheless scholarly and insightful.