Christ but not Jesus?

In response to an earlier post on Christian preaching of the Old Testament Bob MacDonald makes the intriguing suggestion that perhaps not all NT references to Christ refer exclusively to Jesus.  I have to be honest I find this highly problematic on a number of fronts, but wasn't sure which particular texts Bob might have in mind.  When pressed he suggests Col 1:24, "in my flesh I am completing what is lacking in Christ's afflictions for the sake of his body, that is the church."  To me the reference to "affliction" (θλῖψις) unmistakably invokes Jesus' passion.  In the gospels this word is usually used of eschatalogical tribulation, not Jesus' suffering per se, but in Paul's letters it is mainly used to talk about suffering caused by external circumstances, e.g. Rom 5:3, 1 Cor 7:28, 1 Thess 1:6.  Not only that but in Colossians it is a particular suffering for Christ's body the church.  (This idea of the church as Christ's body frequently causes confusion, but it is simply a possesive genitive, the body corporate that belongs to Christ.)  Now in Paul's thinking who suffered for the sake of the church's salvation? Was it a nebulous formless cosmic "Christ" or was it the human Jesus, the Christ, who suffered and died "in his fleshly body . . . so as to present [the church] holy and blameless and irreproachable before him."(Col 1:23)? 

Now none of this solves the problem of what Paul finds lacking in Christ's sufferings, or how his suffering helps complete it, but that is a topic for another post.  Suffice to say I'm not convinved that the NT ever talks about Christ with out exclusively intending to denote Jesus.