So the very first thing is that any Christians who wanted to reject any such finding, could, and would, very easily just point out that the claim is impossible.
...
They could, and certainly would just say that the discovery of any such bones was proof positive that Jesus lived. And after he lived, he miraculously became a holy spirit ... which is what he really was all along.
This would require more effort in solving an obstacle than is currently employed today where no effort is required as the absence of the remains is already accounted for and plays to the religion's favor.
I am not claiming that it would end Christianity; only that it would require address and that address would not be small - let alone would the opponents to Christianity let the situation just slide by. No, the opponents (such as Sam Harris, or his kin) would drive the point in repeatedly.
Even in your account, the imagined Christian has to change stance and excuse away the evidence rather than embrace it as proof of some form outright.
Your provided imagined Christian just reshaped a rather radical belief system of the Christian theological grant to the authority of salvation, in that a very large reason that the physical remains being brought back and taken up in the likes of Elijah (that is, physically ascended to Heaven) is quite regularly outlined as important because the resurrection of the physical body is part of the domain ownership of what authority the salvation of Jesus has.
Craig used CARM before, and I find no fault in doing so:
"The resurrection of Jesus is so important that without it Christianity is false."
But let's just check around and see what some others think:
"The physical resurrection of Christ is the cornerstone of our faith. Without it, Christianity crumbles.
...
Furthermore, the confessions of Christianity are replete with references to the physical resurrection of the Redeemer. Cyril of Jerusalem proclaimed, "Let no heretic ever persuade thee to speak evil of the Resurrection. For to this day the Manichees say that the resurrection of the Savior was phantom-wise, and not real.""
http://www.jesus.org/death-and-resu.../did-jesus-physically-rise-from-the-dead.html
"Virtually all Christians believe in the resurrection of Jesus – it should be all Christians, but there are some people who self-identify as Christians who do not actually believe in the physical resurrection of Christ. Obviously, such people are not actually Christians – the physical resurrection of Christ is of paramount importance in Christianity. As Saint Paul says, if Christ was not resurrected our faith is in vain (I Corinthians 15:14) – if Christ did not actually die and was not physically raised from the dead, how can our sins be forgiven by the death of Christ?"
http://www.catholicbasictraining.com/apologetics/coursetexts/6i.htm
"Jesus made a special appearance to Mary Magdalen and to another or other women. The women clung to the feet of Jesus as if to make sure He was real; they did not wish to let Him go. This Gospel detail shows the reality of Our Lord's, risen body, which was not a "ghost" or an apparition. It a real, physically tangible body."
http://www.catholictreasury.info/lord2.php
"PART ONE
THE PROFESSION OF FAITH
...
643 Given all these testimonies, Christ's Resurrection cannot be interpreted as something outside the physical order"
http://www.vatican.va/archive/ccc_css/archive/catechism/p122a5p2.htm
"The Resurrection of Christ has much in common with the general resurrection; even the transformation of His body and of His bodily life is of the same kind as that which awaits the blessed in their resurrection. But the following peculiarities must be noted:
Christ's Resurrection is necessarily a glorious one; it implies not merely the reunion of body and soul, but also the glorification of the body.
Christ's body was to know no corruption, but rose again soon after death, when sufficient time had elapsed to leave no doubt as to the reality of His death.
Christ was the first to rise unto life immortal; those raised before Him died again (Colossians 1:18; 1 Corinthians 15:20).
As the Divine power which raised Christ from the grave was His own power, He rose from the dead by His own power (John 2:19; 10:17-18).
Since the Resurrection had been promised as the main proof of Christ's Divine mission, it has a greater dogmatic importance than any other fact. "If Christ be not risen again, then is our preaching vain, and your faith is also vain" (1 Corinthians 15:14)."
http://www.newadvent.org/cathen/12789a.htm
"The Bible tells us that when Jesus returns to earth, he will physically raise all those who have died, giving them back the bodies they lost at death."
http://www.catholic.com/tracts/resurrection-of-the-body
"...the belief in Jesus' physical resurrection remains the single doctrine most accepted by Christians of all denominational backgrounds."
http://en.wikipedia.org/wiki/Resurrection_of_Jesus#Resurrection_and_Redemption
This could continue for quite some time, but the basic point is that it is rather central to the general Christian theology.