Finally snow! This seed generates a massive snow world with snow, snow, and snow, and requires Minecraft 1.9 (pre-release) which you can find and download at Minecraft Forum. The seed is this:
Click the "read more" for more screenshots and info.
If you want just snow, this seed is for you. Here's a map showing you my initial spawn point and, well, snow (click for larger preview):
At x = 175, z = 110 there's a very deep cave which goes really deep - the y-coordinate being under 13. There's a very long waterfall and good easily gatherable resources like coal, iron, and obsidian.
At x = 275, z = 80 there's a cave which leads to a zombie dungeon with a chest (contents below).