They were hand made and wear strange name sometime. In some market, was the case in France, were sold as Ruffino Italia 2000, Ruffino as a make.
http://carcatalog3.free.fr/que18.htm

But for the Intermeccanica, Italia is the model name rather than the make/brand, no?
And for the Triumph one, was it sold as a Triumph? If it was just sold as "Italia 2000" it is normal that it does not appear as a Triumph.

The IMCDb database lists only one car under the heading 'Italia' but there have been at least three different types of cars built with that name; two of which are in the IMCDb database.

Technically, the car listed as an Italia 2000
http://imcdb.org/vehicles_make-Italia.html
should be listed under “Triumph” as the ‘Triumph Italia 2000’.

Listed under ‘Intermeccanica’ is the “Intermeccanica Italia.” Which has appeared in at least three movies/TVshows. http://imcdb.org/vehicles.php?make=Intermeccanica&model=Italia&modelMatch=1&modelInclModel=- on

Hudson also made 26 cars called the Hudson Italia based on their Hudson Jet chassis – but apparently these have never appeared in any movies as they are not in the IMCDb database.

Unless one is talking to a Triumph-only crowd, or a Hudson enthusiast, any mention of a car called an “Italia” is most often thought of as referring to the Intermeccanica Italia (of which over 400 were built). Therefore, I recommend that either the IMCDb database include the Intermeccanica Italia under the “Italia” listing, or else the Triumph Italia 2000 should be moved under the “Triumph” category.