All the duchies I know of are spoken for.
If you can carve one out of BoM, it's all yours. 
Think about all the benefits of living in the Frozen North:
+ Free life-time supply of slushies and other icy treats!
+ Skiing! Snowboarding! Yeti wrestling!
+ The Vikings are drunk, pliable, and complacent. There would be no pesky nobles plotting your downfall from within your own realm.
And that's not all!
You get life-time immunity from CE! Seriously. It's too far away and too cold. The last time Enri marched up there half of his laser bears troops froze to death.
You forgot inappropriate goat actions!
And total lacks of bathing!
And extensive nudity made up for by ludicrously long beards!
