I sure wish I lived closer to all you unfortunate souls.. I do mouse control for a living. My company specializes in the removal of mice/bats and structural sealing.
Some tips:
-Ultrasonic mouse repellants do not work
-Cats will keep mice from running acroos the livng room, sometimes, but will by no means keep them out of the house.
-Steel wool is an excellent deterrent to keep mice from going through a hole, but only if you remove the original mice first, otherwise they will make a new hole somewhere else. There is a spray foam that contains a rodenticide that will also prevent them from chewing.
-Mice can walk up a brick wall as easily as walking down the driveway.
Mouse traps will "train" the mice to avoid mouse traps, when you stop catching mice it doesn't mean they are gone, it means they got smarter.
-90% of the time mice start in the attic, work their way down the inside walls to the basement, there they get on the hot water lines and follow them, go look under the kitchen sink and you will see. Once mice are under there you can be assured you have a problem.
-Bait/poisons are the ONLY way to stop the problem, the keys to this is to spend some money, you get what you pay for with that stuff, skip the hardware store and go to a farm supply place, they tend to get better stuff. Good bait will prevent mice from dying inside a house, thus avoiding the smell. When using baits, keep a constant supply, THIS IS VERY IMPORTANT. Never let the bait all dissapear then start again.
Bait the attic first, the mice will be drawn to the attractants in the bait where ever you put it, if you put it in the living room you will have mice in the living room. So stick to the attic, they will all be there eventually anyways, and a little bonus is the safety issues of having a bait in the living quarters of your home.
-The fear of an animal cat, dog, preditor birds... Finding the dead mouse and consuming it are WRONG. The amount of bait in a dead mouse is NOT enough to affect a domestic animal, also the active ingredients are mostly depleted. None of you have the ability to purchase a bait strong enough to cause a "chain" effect with a poison. Otherwise you would already know what I am telling you.
-There is no such thing as "a mouse" if you can see them you have a problem. Educate yourselves on the health issues of mice and their droppings for you and your family.