WHO YA GONNA CALL? FATBUSTERS!: I wonder how long it will be before those clever Japanese figure out how to fit this fat busting microwave oven they've just invented into a tanning salon machine. Millions of overweight Americans are looking for a way to lose weight without exercising or giving up junk food and get a good tan while they're at it. The Japanese could get a licensing deal with Wal-Mart; every superstore in the country would get a weight-loss tanning salon, preferably next to the aisle with the ten pound economy size bag of potato chips and the boxes of Coca-Cola, ensuring that the customer base would never disappear. The market is there, people; it only takes an entrepeneur of genius to go out and sell the concept to the nation and the world. Emerson was right: build a better mousetrap and the world will beat a path to your door.