Yes, but now you are going beyond the scope of Scripture to prove your point, which is not Sola Scriptura.
Sure it is. Sola scriptura as the refomers defined it (and I am confessionally reformed) did not say that their was no authority outside of scripture, just that the scriptures are the sole infallible authority for doctrine. It is a reaction to those who appealed to the custom and traditions of their churches to establish doctrine and bind the hearts of believers.
If you take into account the writings of the early Church fathers on Scriptural sufficiency, then you must also take into account their other writings such as their belief in Apostolic Succession, Confession, ordination, the Real Presence, Apsotolic Tradition, etc.
a few thoughts here:
1) I do take those into account. I spend a lot of time reading them and trying to figure out how Church history fits together.
2) The establishment of your religious authority (church, tradition, reason, scripture, etc...) is not identical to beliefs on such things as baptism and real presence. What you see as your authorities will determine how you view these other issues because it establishes where you getyour imformation about those beliefs. Ergo - this issue in particular is of paramount importance and relevence above the others you listed.
3) I would add that the equation goes both ways. I critique your view of scripture and tradition because I think it is a foreign to the dominant patristic view, and you may in turn critique my other views as being foreign to them as well.
4) I should add as well that depending on how you view the fathers views of scripture could radically affect how much their own teachings will affect your views. To the extent that you see them as authorities in their own right will determine how you interact with their views.
This topic is about the authority of the Bible alone, and my point was simply, that the Bible itself indicates that there were teachings and traditions passed down that were not recorded in writing, which suggests their could be an extra-Biblical presence of authroity.
Most Christians I think would agree with this to some degree if they thought about it (i.e... my example of the canon, or the fact that Jesus spoke other words not recorded in scripture). If that's all you claim, I don't really have a big problem with it.
Where the issue becomes contentious is when claims are made that specific teachings are apostolic traditions (such as the IC, or papal infallibility). The issue is, as always, whether supposed oral traditions from the apostles or Jesus really are such or whether they are illegitimate accretions to the faith.
ken