Well there you have it Pinetree. You are absolutely, 100% correct, and have been so all along! There is no biblical support for a "Spirit-filled Christian" to be "demon possessed". You can walk away from this one proud, knowing that no one here has been able to confuse your already convinced mind with any of our ridiculous facts!!
Never mind that there is no such scriptural thing as anyone being "demon possessed", Christian or otherwise.

Forget the problem of resolving the questions of why people who have accepted Christ still display symptoms of demonic influence; and are helped by others casting spirits out in the authority of Jesus. "Experience" is a evil word; and nothing we do should be guided by those who have any of it, should they? We should all hope to learn the most "Truth" from those who have the least experience... because it is they who are the least likely to be confused by what they have encountered in life as compared to those who get their information directly from the Bible (or lack of mention therein) (sitting back in their armchairs reading rather than actually going out into the World applying the Gospel message!)
This thread has failed IMO as the "Final demon thread", as there is so much more that could be discussed. We haven't even touched on the difference between demons and unclean spirits! But you were quite insistent that we only speak about "demon possession", and how it relates to the scriptures; so that is what you've got! No scriptures anywhere to convince you that "demon possession" can occur in a Christian! There you go! Happy??
Oh, and one other bonus. This probably is the "final demon thread", at least where anybody on this forum willingly chooses to talk to
you about it!
God bless you, brother!
Tobias -- living my "Experience-based" Christian theology!
Because God is meant to be experienced, not just talked about!