I noticed on my Cleric the changes were quite small, but the names of the skins hint that I should be seeing some change, where I'm seeing nothing. The skins are called things like "Tan-Coated Badger" or "Dark-Back Badger", but they all seem identical. Not even a size change.
I have two other capes, the Maelstrom Cloak and the Cloak of the Ashmadai and I can use the combiner to make one of them look like the other, or even make a necklace take on a cape's appearance, but the Caturday Cape doesn't let me put it in the "Appearance" slot.
Hmm, that's odd. I have a cape I got from one of the first dungeons, but it won't let me re-skin that one. Maybe only some capes have that feature turned on? I'll have to find another one.