Hi Morten,
www.classicfootballshirts.co.uk/International-Teams-European-Norway/c23_78_242/index.html
I know you've probably seen that site before, but they usually get different/updated shirts about 2-3 times a year. They're also pretty pricey, but they seem to lean more towards match-worn than just general jerseys.
Speaking of, if you ever need someone to look out for a specific shirt, drop me a line:
bonnie.lassie (AT) gmail.com
Even if I don't end up buying a certain Norway shirt due to price, being outbid, etc., I keep an 'archive' of images with the years and any special notes (match worn, third shirt, years, etc.) on them so I'll have them to compare when other shirts pop up for sale.
I really have no helpful suggestions at all for the club shirts. I have some friends in Oslo and I'll have them ask around. Maybe there's a Norwegian site/place I've not heard of.