Not true, though ...
If you think of the shift as being on the stack, and you play a "reduce damage dealt by target spell to zero, draw a card." .. you can resolve your card, then play "counter target green spell." since the hurricane is still on the stack.
Well looking at it from a pure MTG point of view I'd say it'd look like:
Shift on the stack.
OA from Warpriest on the stack (triggered by the shift)
OA from Warpriest resolves.
Combat Challenge Mark goes on the stack.
Combat Challenge Mark resolves (target is re-marked)
Note: shift is already on the stack and thus does not trigger Combat Challenge again.
Shift resolves.
Now this isn't exactly what happens for 4th Ed. Its not terribly clear when triggered actions (whether OA or combat challenge) are triggered. Is it the declaration of a shift? Is it when a shift happens?
In the first case it works the same as Magic and the double attack does not work.
In the second case, any interrupt would actually need to "re-wind" time so that it occurs before the triggered action "happens". In this case the double attack thing WOULD work because once the first interrupt was finished the shift would "happen" (for lack of a better word) again which would trigger the combat challenge, which would rewind time and get to happen before the shift.
Note, however, that in that last case the double attack would only occur if the warpriest OA missed, because as a fighter your OAs that hit stop movement. As such the shift would never "happen" for a second time, thus not triggering the combat challenge.