The movie Cabiria (1914) is considered the greatest of the Italian epics and extremely influential in future films such as Intolerance (1916) and Metropolis (1927). It paved the ground for future historical films and astounded audiences with its convoluted storyline and ambitious scale.
Unfortunately, the most complete public version we have on popular media outlets (Netflix, Amazon, YouTube) only runs 126 minutes. However, there is a 2006 restoration of the movie that extends the runtime to 190 minutes - only three minutes short of the original film. It was first screened at the Palais du Cinema in July 1, 2006. This version is mentioned on Roger Ebert's website and on Wikipedia: www.rogerebert.com/reviews/great-movie-cabiria-1914 en.wikipedia.org/wiki/Cabiria
At the bottom of his review it states "The Criterion Collection is preparing a DVD edition of "Cabiria."
It seems probable (considering it has been 10 years now) that a public version is not planned to be released anytime soon. If we could contact those responsible for the restoration it is possible we could receive some concrete proof on a release of the extended version.