Some other hadith material wich refers to the quran's incompleteness.
1. It is reported from Ismail ibn Ibrahim from Ayyub from Naafi from Ibn Umar who said: " Let none of you say 'I have acquired the whole of the Qur'an'. How does he know what all of it is when much of the Qur'an has disappeared? Rather let him say 'I have acquired what has survived.'" (as-Suyuti, Al-Itqan fii Ulum al-Qur'an, p.524).
2. We used to recite a Sura which resembled in length and severity to (Surah) Bara'at. I have, however, forgotten it with the exception of this which I remember out of it: "If there were two valleys full of riches, for the son of Adam, he would long for a third valley, and nothing would fill the stomach of the son of Adam but dust" (Sahih Muslim, Vol. 2.p.501)
3. "God sent Muhammed and sent down the Scripture to him. Part of what he sent down was the passage on stoning, we read it, we were taught it, and we heeded it, The apostle stoned and we stoned them after him. I fear that in time to come men will say that they find no mention of stoning in God's book and thereby go astray in neglecting an ordinance which God has sent down. Verily stoning in the book of God is a penalty laid on married men and women who commit adultery. (Ibn Ishaq, Sirat Rasulullah. p.684).
4. A'isha (Allah be pleased with her) reported that it had been
revealed in the holy Quran that ten clear sucklings make the
marriages unlawful then it was abrogated (and substituted) by five
sucklings and Allah's Apostle (may peace be upon him) died and it
was before that time (found) in the holy Quran (and recited by the
Muslims). (Sahih Muslim, Vol. 2, p. 740).
5. In one of the six most authentic Hadith books by Ibne Maja we find a parable told by Hazrat AyshaR, in which she says:
"The aa'yaa on rape and nursing of babies were lying in book form, that was kept in the patio. When the Holy Messenger passed away, we became busy in his funeral. During this time, our domesticated pet goat ate the manuscript of these two aa'yaa. And so these aa'yaa were wasted."
6. There are seventeen thousand Ayah in real Quran. (Al Shafi, Vol. No. 2, Page No. 616)
Seems like RomeSweetRome used a couple of these allready, didn't see it, sorry if i'm repeating.