I'm probably not going to get a Battlecruiser. However, I'm definitely considering swapping or selling one of my fleets to facilitate getting more stuff (for example, there's a guy I know from BMG events who's wanting to swap his Scourge for UCM). There's no way I can keep up with the arms race with two fleets - I have enough trouble with that with the Resistance.
The cruise liner is apparently a scenario piece and the stat line will be freely available, so technically you could use anything for it. I have a couple of models that might work, depending on size.