Fallen Kayle and Angel Morgana?
I've mentioned this idea to a couple of my friends over the past month or so, and they all agreed it was an interesting concept. I don't know if it's been posted before, but I scanned the most recent posts and didn't see anything on it. Even for 520 skins that don't change any effects or abilities, I think they'd be neat ideas. Sorry I don't have a mockup or anything, but I'm not artistically talented.