As far as I know it's pretty much 50% pork, 25% beef and 25% potatoes. I think we've added more beef since my grandma's time though. As they didn't have beef cattle - only a couple of cows for milk, cream and cheese - beef was kind of a luxury. And yeah, that's the only type of korv we make with potatoes as an ingredient. Other than the meat and potatoes we use the stock we get after making our julskinka (christmas ham). Milk and cream also goes into the mix, though I'm not sure how much. For seasoning I only know that they use ginger and allspice, but I'm sure there's more than that. No onions anywhere.
Sorry if that wasn't too informative - I can design a processor from scratch, but cooking is rocket science to me :(