Dieter,
Just thinking of a course I have played recently, the 14th at Pasatiempo comes to mind. I doubt there is any significant elevation change from tee to green but the undulations in the fairway, which are probably no more than 6' or two meters, really make the hole interesting. Not sure if I would call it a signature hole because the undulations would not show up that much on a photo as would water, a deep drop, etc. but it is a very interesting and respected hole, especially from what I have seen from those on this website.
Regards