The People of the Book (Ahl-ul Kitab) are granted a particular status in Islam. The Christians and the Jews, those who received and follow the previous scriptures, are easily counted among their number.
Mormonism, on the other hand, was founded over a thousand years after the time of the prophet. Although ostensibly they follow the Bible and are thus an extension of Christianity and Judaism, they also follow the scriptures revealed by Joseph Smith, who they claim as a prophet.
Since they follow teachings based on the Bible, they could be considered "Ahl-ul Kitab" in the same way as the Christians. However, since they have superseded the Bible with their own scriptures, scriptures which are not known in Islam, it is unclear whether they would be classified thus or not.
Has there been any major scholarly study on this matter? Should the Mormons be treated the same as the Christians and the Jews so far as rulings are concerned?