A buddy of mine has a factory in Lake Zurich off of rt22. They do indoor heated storage of cars and boats......they are actualy getting away from storing boats but wont turn people down if they ask about it cause they make more money stroring classic cars then boats. Anyway they are charging like $35 a foot for the season. If interested you can call Eric at 847-438-3330
Oh and you can also work on your boat if you make arrangements with them in advance. I'm at the factry working on something most times during the weekend nights and they are cool with me being there when they are not around if anyone else wanted to work at the same time at night.