I have never seen a Q400 get even close to a tail scrape (appart from when the Bombadier test pilot - named 'Wally' - nearly did it on certification - but there was probably a very good reason as to why this nearly happened).
What I have seen frequently is the Q400 running over lights, runway designator boards (Augsburg) and taking short cuts across the grass with one of their main wheels as they vacate the runway. It seems that the combination of a wide track and the nose wheel being far forward makes them quite good at this (especially if the pilot follows the yellow lines with his nose wheel).
Now that they can park on just one stand (nosewheel mod) they are very capable aircraft in and out of City. I saw an SAS aircraft rotate half way down the runway, and then get to 3000ft long before he made the initial turn at 1.5DME. I can't remember another aircraft having this performance (or maybe the load figures aren't doing too well to Copenhagen).
I also remember seeing an Augsburg one land abeam the tower (on runway 28) and still come off at 'B' so they seem to stop even better than they go.