I like this. I don't like the requirements including 1d6 eldritch blast, because then you have to build a character just for this prestige class. And I hate that.

But it's an excellent barbarian Prc. I also like the idea of a 20% chance for the rage continuing. Maybe 20% plus 5% per class level?

Also, I get the impression that this DR is similar to the barbarian DR, and as such shouldn't be DR/cold iron. But hey, whatever.