@janeto, I really love the Craft brand in particular - the Craft Glide Full-Zip Pant has both the front and back wind resistance you're looking for. These would be great for those really cold days in MN where you need that 360-degree protection, but you might want to also consider a front-panel-only wind-proof area for less extreme days to provide the protection you want without that sweaty-behind-the-knee feeling.
Look especially at tights/pants designed for cross-country skiing! XC ski bottoms have various windproof configurations and all the stretch and articulation you need for running. What they sometimes lack (because it is assumed you will be on trails) is the kind of reflectivity you need when you run on roads or on trails frequented by snowmobiles. So, be sure you are visible and/or add reflective ankle bands and vest.
Another borrow from the xc ski world is insulated shorts in a length that covers most, but not all of your thigh. These come in wool or synthetic with windproof panels in the front and can be worn under regular tights. Sometimes that gives just the right amount of protection without overheating.
Good for you for keeping up your running in winter. Dashing through the snow is awesome, right?