Remember also that Christ took on the full punishment for our sins-- not only physical death, but also spiritual death (hell), which is generally defined as meaning separation from God. This is affirmed in John 19 when it tells us that, on the cross, Christ's body and His spirit were separated.
Thus, for Christ to truly take on the punishment for our sins, it would mean a separation from God. And, to me, that seems to imply that His divine nature-- perhaps rendered in John's Gospel as His "spirit"-- left His human body at the point of ultimate salvation on the cross.
I'm tempted to stop you at the beginning of that and say that not all Christians believe he was really in hell at that point, but you make a good point about the body and spirit being seperated.
I think this also raises some interesting questions about the nature of the trinity - Did Jesus raise from the dead of his own power (as the son), or was he risen by the father or the spirit? If he was incarnated but without his divine component, what would death mean to him - does he have a spirit besides that? Would it be spiritual hell to be personally divided like that and seperated from God, even if he wasn't in hell as we like to think of it? Would that seperation be a far-worse punishment than any ordinary hell we could fathom, thus making a far more substantial sacrifice for sin than we could ever think of?
This poses more questions than it really answers. Good thoughts though.