I don't know if this has already been done before but I think it would be cool to do. I am not going to make this since I have no idea where to start but if you would like to make this go ahead I would like to see this idea come to life.

Possible features:
.Lots of wild snow golems
.Sleigh
.Christmas trees - can be put in pots on 1.4.2
.Christmas tree light - powered by redstone
.Leave a chest with milk and carrots in by morning it will just be an empty bucket
.Santa outfit armor
.Present - a chest with items in on Christmas morning
.Christmas eve you can hear jingle bells
.Christmas songs for jukebox
.new mob - Wild reindeer - Found in snow biome
.new mob - mouse - Found in wooden structures
.snow bricks
.snow brick block
.new structure - igloo

.new biome - north pole
.new structure - Santa's workshop (Can only be found in the North Pole)
.new mob - elf (Can only be found in Santa's workshop)
.new mob - Santa (Can only be found in Santa's workshop)

Suggestions:
Eggnog - lordhaha1

IF YOU WANT TO ATTEMPT TO MAKE THIS LET ME KNOW OR IF YOU HAVE ANY IDEAS YOU WANT TO ADD JUST COMMENT BELOW