Riot, I'm on my knees and openly pleading with you. Allow using wards on Twisted Treeline, BUT!...
...They don't actually provide vision or anything, changing absolutely nothing about the mode.
However, this would allow people to make use of their ward skins on the map, giving them value to players like myself who much prefer Twisted Treeline to the traditional Summoner's Rift (I don't dislike SR, I just like TT more!).
My existing ideas for how to actually implement this easily are all gone (biggest one was active effect on boot items), so I leave it in your hands to figure out an elegant solution to it. Just please, please make this happen! It's so frustrating to not be able to make use of my ward skins...