Dwarven (I agree about the height, weight, and beard comment) warlock 8 with the Spider Climb and the dimension door invocations (for those extra-tight chimneys). Handle Animal for the magic reindeer, and the take 10 on UMD + crafting abilities to make the sleigh. Not sure what to do about scrying on every kid in the world... maybe he has one of those magic mirrors?
Make him also a Proxy of an unknown deity.
The SDA the proxy gets, works just like the Pazuzu-Pazuzu-Pazuzu ability.
Rudolph's red nose can see through Solid Fog, with a strange Light effect.
That's definitely Artifact level (though not otherwise strong).
Warforged + Docent + lots of Polymorphing.
Who says those are Reindeer Horns? They could be implants.