I have a 1600sq ft 2 story home in Brooklyn Michigan. I have base board hot water heat and no ductwork. Want to add central air conditioning. There is an attic with 24x48 pull down stairs. No attached garage, but a 18x20 garage very close. Don't want the Mitsubishi Mr Slim. Heard of 2 inch pipes uses to blow cold air into rooms.
Any thoughts for central air in this situation?

Space pack web site is what I believe you are looking for. I highly recommend professional install on this item.

http://www.spacepak.com/

I see you have attic do you also have a basement?