I love commercial ships, freighters as well as liners. One really nice kit you might look at, even if not a liner, is the container ship by Revell of Germany, the Colombo Express. There have been several threads in this forum on it, with some nice pix of folks builds.
One subject, not quite a liner, but close, that I'd like to see, but probably fat chance, were those river liners like they ran on the Hudson in late 19th Century, side wheelers, enormous palaces of gingerbread. Big walking beam between engine and the wheel drive. Ornate paddle boxes (PE, maybe?). They were also run on some of the bigger lakes in the NE, and in Long Island Sound.