Those who are suggesting some type of edged weapon have a point, that is if they are not illegal too in Norway.
Cold Steel sells a stabbing spear which really would be deadly. Also an Ontario machete would scare the dickens out of me if someone was threatening me with one.
Cold Steel katana demo.
http://www.youtube.com/watch?v=u3nAuowwqhI
Yes, they are illegal in Norway...you can be arrested for carrying something bigger than 2” I believe.