As long as we are saying things we've said before, one can have a lightweight extended keyboard with great action: e.g., the Nord Electro 73, which weighs 22lbs and the Nord Stage (88-key, hammer action) which weighs about 45 lbs. These synths use metal casing, not plastic. It is almost as though manufacturers intentionally make their high-end arrangers heavy to increase their perceived value. The smaller and lighter is better value that applies to laptops and cell phones has not really reached arranger keyboards.