I am sorry and I don't want you to feel guilty but cats are in worse shape then dogs when given up..and this includes kittens if you are looking for a young one.
The first link is to the Breed Club like the YTCA and from there you can go to their rescue site or look at some of their breeders.
UMCCA - Breed Rescue United Maine Coon Cat Rescue League Maine Coon Cat Breed Rescue - Maine Coon Cat Adoption Maine Coon Rescue NY Petfinder Site East Coast Maine Coon Rescue