It's not really Ravenlofty, but maybe this can be of use in some games. (The product describes the religion and avatar of Benten, a goddess of luck, love, and the sea.)
The following is Open Gaming Content, taken from "Divine Forces--Benten: The Golden Goddess of Good Fortune" (Author: Steve Miller, Copyright ©2006 Interactive Design Adventures and Steve Miller).
Benten’s Headdress of Stealthiness
This artifact appears in a virtually endless number of forms, but it is always some sort of headdress; the wearer decides what sort of headgear it becomes when they don it. When worn by Benten's avatar, it usually appears either as an ornate, gold-embroidered bonnet, or as a gem-lined platinum caul that shimmers over her raven-black hair.
The ability to appear as any kind of headgear is this artifact’s most minor power, but it’s Benten’s favorite aspect of the item.
When worn, the headdress grants its wearer total protection from all divination magic, except that cast by a greater god, and gives the wearer a +10 divine bonus to Sleight of Hand and Move Silently skill checks. In addition, by offering a small prayer to Benten (a full-round action), the wearer may invoke the headdress ‘s ability to render him or her completely invisible. The wearer remains invisible until he or she takes an offensive action, or until subjected to dispel magic at a 25th level effectiveness. Even true seeing cannot overcome the power of this artifact.
Benten often lends the headdress of stealthiness to lovers who are forbidden from seeing each other, or to jealous women who want to spy on their spouses. When she lends it, she makes it clear that the lucky mortal has the headdress for a specific purpose and for a limited time. Once it has been used for that purpose, it immediately disappears from the borrower’s possession and reappears in the treasure hold of Takara-Bune.
If a mortal fails to work toward reaching the goal that he or she was lent the headdress to accomplish but instead uses it for other purposes, Benten eventually loses patience. In such a circumstance, she waits until the character is using the headdress and is at a key and very dangerous moment in whatever stealthy action he is taking. Benten appears and says that the headdress was lent to the character not gifted, and that if the character can’t use it in accordance with the terms of the loan, she is taking it back. Benten and the headdress then vanishes, leaving the character exposed to whatever threats are present.