You say that the sunan are not derived from the hadith books but they have reached to us by the ijma and tawatur of the Muslim ummah. But in many of your various articles you mentioned that hadith books besides having the record of some historical facts and other things do have a record of some of the sunan. Thus the statement that the hadith books do have a record of "some of the sunan" clearly implies the fact that hadith books do not have the record of all the sunan. So on the basis of this statement I ask can you mention a single sunnah which has reached to us by the tawatur and ijma of Muslim ummah but has not been recorded in a hadith book?
If the sentence "Hadith books have record of some Sunnah" implies that there is a Sunnah that is not at all referred to in Hadith literature then I think the sentence does not carry an accurate message. I have not checked it one by one but from the outset the impression I get from the vastness of hadith literature is that it does have mention of all the content of Sunnah.
However, if the above sentence implies that not all of the Sunnah has been recorded clearly and categorically in the Hadith literature then I agree with it. To give you an example, just imagine how difficult it will be if a person tries to learn how to do his prayers from the scratch and with no background knowledge purely using books of Hadith. Moreover, it will not be easy if at all possible) to distinguish between Sunnah of the Prophet (sws) and those practices of the Prophet (sws) that are not part of his Sunnah, purely with the use of Ahadith.
Either way, the important thing to appreciate is that we do not need Hadith to learn the Sunnah of the Prophet (sws). The Sunnah of the Prophet (sws) has reached us through a much more reliable and clear source, that is the ijmaa and consensus of the Ummah.