The market (performance/show) isn't all that great in the north because of the seasons. I'm not saying there isnt one, or that you cant find fast/nice cars in the north - there's plenty of them. But from a business standpoint, I would imagine there would be too many slow/down times and it would put too much strain on the business.
Keep looking thought cuz they are around, you just might have to take a drive to find a worth-while place. Good luck!