If we had an interchangeable front pairing it's actually a tactic that can work as most full backs hate having to commit themselves to challenging big guys in the air. I don't see us doing it but quite often away sides have targetted our full backs with long crosses on the basis their big centre forwards can give them a stuffing in the air and either get a good header in on goal or find their strike partner close to goal. It used to happen a lot with Taylor and, going back to a recent discussion, that is what Derby did with Martin/Peltier for their second goal.
I remember Norway playing Tor Andre Flo (Sp?) on the wing against England and demolishing England's full back with long diagonals in the Graham Taylor era.
Used to do it myself in Newport and District until a burly full back got fed up with me out jumping him and smashed my nose when the ref turned his back!!! Nothing to do with me stamping on his foot first of all of course.