The Orca is currently one of two known passenger ships, the other being the Dolphin. In the current game Template:CurrentVersion there is not much difference between a passenger ship and other ships except for the sleek and fashionable design, long windows, and luxurious interior.
[r] = Reserved slot: default system cannot be changed.
Notes
Initially decals could not be fitted. Now they can and even some basic paint jobs are available (Vibrant pack)
The Orca is the only ship in game that cannot fit a optimal sized shield. It requires a size 6 for optimal, but can only take a size 5 in one of the size 5 slots.
Related to the above, one of the size 5 and the size 6 slot can only have hull reinforcement or cargo modules. It is unknown as to why this is at this time, but it is speculated that these are meant to be reserved for Passenger Cabins. It is quiestionable though why then you can still fit hull reinforcements and cargo modules if they are meant to be reserved.