Place turkey carcass in a soup kettle or Dutch oven and cover with water. Bring to a boil. Reduce heat; cover and simmer for 1 hour. Remove carcass; cool. Set aside 3 quart broth. Remove turkey from bones and cut into bite-size pieces; set aside.
In a soup kettle or Dutch oven, saute the onions, carrots and celery in butter until tender. Reduce heat; stir in flour until blended. Gradually add 1 quart of reserved broth. Bring to a boil; cook and stir for 2 minutes or until thickened.
Add cream, rice, salt, bouillon, pepper, remaining broth and reserved turkey. Reduce heat; cover and simmer for 30-35 minutes or until rice is tender.