And there lies a problem (for me at least). It's not that I am against adding new designs in itself. But the last thing we need is yet other Forgotten Realms oriented items. There are way too many of those already. I would much prefer new items to be rooted solely in Ravenloft's lore. This is the Demiplane of Dread, and whatever is added should be to enhance that identity.
The issue being that those cloaks do not exist. But I also do not see problem with simply implementing the ability to at least let those people who do indeed play Forgotten Realm characters, pick a cloak with the matching symbol of their diety. I don't think there's gonna be any more/less of those characters around, with or without the cloaks.