Prepare rice according to package directions.  Add milk, coconut milk, sugar and salt to cooked rice.  Simmer 25 minutes, stirring occasionally.   Remove from heat and add 2 tablespoon rum.  

In a small saucepan, combine cornstarch, brown sugar and pineapple with juice.  Cook over medium heat until thickened, about 2 minutes.  Remove from heat and stir in butter and remaining rum.  

Serve pudding topped with pineapple sauce and garnished with coconut.