This is my luxury liner build. I use it whenever I feel like doing some passenger sightseeing missions. Like you said Dutchman141, the Beluga overheats pretty easily. Besides the poor heat handling it has terrible shields as well. I use this configuration to solve the heat issue and compensate for the poor shielding.
Because a passenger liner doesn't require much power you should definitely go with a low emissions engineered power plant. Also despite what is said engineer your thrusters with the dirty drive enhancement. This will not cause the Beluga to overheat if you engineer your power plant accordingly. You can get as low as 6D thrusters and still have better performance than 7A rated thrusters. Scooping stars will also no longer be an issue with a low emissions power plant. You can now also use silent running without the ship heating up fast after exiting the space stations if you have scan sensitive passengers. Combined with heat sinks this is now very effective.
Due to the optimal mass of class 5 and 6 shields and mass of the Beluga even the highest class you can put in will give you very poor shielding. I tried to somewhat improve this by adding flat shield absorption using Guardian shield reinforcement packages and E rated resistance boosters. Because of the poor shield strength increase due to the optimal shield module mass/Beluga hull mass discrepancy, the Beluga shield benefits the most from resistances increase. You can get to a respectable 1K kinetic HP after the modifications. This will help greatly for passengers sensitive to hull damage. The shields will be able to take some punishment from collisions.