The 1/350 Lusitania was originally produced, in the 1970s, by Entex. It is currently available in a Gunze Sanyo box, imported into the USA by DML, so shouldn't be too difficult to find.
Among the differences between the Titanic and the Mauretania/ Lusitania were that the Titanic was almost half as big again as the Mauretania (46 200 tons vs. 31 200 tons), and almost 100' longer. She did, however, have only three screws as against the Mauretania's four, and had a top speed of only 21kt as compared to the Mauretania's 27kt.
The Mauretania, scrapped in 1935, also had a rather longer service life...
Cheers,
Chris.
Cute and cuddly, boys, cute and cuddly!