For the 12V bulbs, if you use a transformer that is centertapped with tap to ground, such that you only have 6V from ground, that might cut the shock hazard enough in such a wet environment (someone standing in ankle deep water trying to change a bulb).
Or some manufacturer will need to develop a fiber optic method such that the bulb itself is far away from the tub, and the pendants are all non-conductive except for grounded metal parts...
