Narcis is a lightweight addon with a singular and very simple function: Saving cosmetic data other than armor between costumes.
Currently, and as a proof-of-concept, I created an addon which will save guild holomark settings (visibility and distance) over various costume changes. This data is persistent through logins. No outside interaction with the addon is required, just set your desired look, and then swap away!
If any following is acquired, I could also look into titles and guild/circle tags as well!