With the tidbit that white and gray items may become Moggable “soon”, a quick look in my RP Clothes bank generates this list of the items I most want to see upgraded to Cosmetic:
White Woolen Dress
Simple Black Dress
White Wedding Dress
Tuxedo Jacket and Pants
Haliscan Jacket, Pantaloons, and Brimmed Hat
Black Embersilk Gown
White Traditional Hanbok
Red Traditional Hanbok
Green Wedding Hanbok
Dark Green Wedding Hanbok
Royal Dangui
Formal Dangui
Burning Robes
Shimmering Silk Robes
Chromatic Robe
Silver Dress Robes
Dalaran Nurse’s Gown
And allow ALL the Holiday clothes to be Moggable year-round, too!
Kamalia et alia 
Since you provided the links, I decided to take a look. These things are loaded with comments! So very cool.
………………….
The white wedding dress was actually popularized in the western world when Queen Victoria was married in white. Before that, brides would generally just wear their best dress, regardless of color.
48
Hinahina on 2010/12/29 (Patch 4.0.3)
Another little fun fact: The Amish traditionally require the bride-to-be make her own gown, and that it be blue. Other Amish communities allow for the bride to choose the colour of her own gown, from burgundy to chartreuse.
It’s kind of surprising to think how modern some of our customs that we take for granted really are!