Some of the reputed builders of furnished apartments in Mumbai are The Lotus Suites, Taj Wellington Mews Luxury Residences, Best Western - The Emerald, Grand Hyatt Residences, Oritel Service Apartments, and Sutra d' Onyx.
It actually depends on the builder what he thinks of a furnished apartment. It differs apartment to apartment. A furnished apartment consists of Wooden Work , Modular Kitchen , Flooring, Fans, Lights, Fall Ceiling, Furniture or AC, with furniture, etc.