Methinks the mistake is trying to find the site of one single great battle, whereas all the extant sources speak of a running three days affair, with the units scattered and mingled with the civilians.
What was found at Kalkriese was indeed questioned. Some even think it is nothing else but the abandoned site of a roman fort of some kind.
In my opinion, what was found are the remnants of one episode of the Teutoburger catastrophe and the scattered remnants of the three legions could probably be found then scattered all along the way across many miles.