That's about all you're going to find... either in the Entex or Gunze boxes, they're basically the same kits, and the Academy/Minicraft Titanic kit is also readily available.
You can, of course, with scratchbuilding, convert Titanic into Olympic and and Britannic in their troopship or hospital ship guises, and Lusitania into Mauretania as either a troopship or hospital ship.
There's a few box scale decent sized liners out there in varying quality, including the Glencoe SS United States...her lower hull shape is all wrong since it was a trade secret at the time the kit was released. That model does require alot of work though.
Best,
Jeff Herne
Modelwarships.com