Not sure if there is such a mod out there, but it would be really cool...

Plenty of snow in Skyrim...plenty of trees and wood to make some sleds...plenty of animals to pull them...considering other populations that lived in such climates made sleds(middle age Viking and Nordic people for example) for both recreational use, travel and pulling heavy objects over snow, I think it might not be in the actual lore of Skyrim, but it would have to certainly be considered "lore friendly".

Troikas! Yeah, I wish. Great idea, hope someone picks up on it!

What about https://lh6.googleusercontent.com/-iNdeI9hHAOU/UrRZRo1bsrI/AAAAAAABN0Y/ZxEktWOciJU/w720-h480/1488150_578313528907445_377233995_n.jpg carriage replacer?

I've wished for this for a long time. The kids will say "look at all the snow! I want to go sledding! Or skating!" at Heljarchen and I think, yeah I'd like that too.