In December 2011 there was a Winter Version of Summoners Rift. For those of you who don't know what I'm talking about here's a picture to jog your memory: [Image Credit: LoL Wiki]
The map (since it's from 2011) appears to be somewhat dated, but core parts of the map are the same (ie jungle locations, and bush places), so I think everything should fit properly. There are no options that I know of in-game to change this, but I know you can install custom skins or custom HUD's. Is there anyway for me to do this with map(s)? More importantly can I legally do this or what are my options?