The idea is simple really, of the characters that have siblings make a skin that's just their sibling dressed up.
Darius skin: Draven dressed up in Darius's armor. Draven skin: Darius dressed up as Draven. Kayle skin: Morgana as Kayle. Morgana Skin: Kayle as Morgana.
Here's the ultimate apex. Garen skin: Lux dressed as Garen. Lux skin: Garen dressed as Lux.
The skins could have the voices redone with the appropriate swap, and give them their own flair.
Lets just be honest you just want a star guardian Garen skin don't you
http://www.deviantart.com/art/Morgkayle-505276311)
For the Morgana and Kayle ones i could see, in addition to the draven and darius. As for the Garen and Lux, unfortunately I do not think that one would fly.
uh cross dressing? That will not go well with the Christian community.
You missed Katarina dressed as Cassiopeia and Cassiopeia dressed as Katarina.
How would figure out who as who with these 3 
and 
?
While this sounds like a cute and neat idea, it's TERRIBLE for gameplay clarity.
