I really struggled to get a pair of decent black maternity pants, in the end I just ended up getting a pair from Target. They're just plain black pants with a bit of stretch, the waist is low, and kind of comes to a v under your belly. I'm tall too (5 foot 9) and they fit fine. I'm pretty fussy with my clothes, not normally a Target shopper, but these are OK.

PS - V jelous over your impending trip in Port Douglas!! We were a couple of hours south of there at Mission Beach in March & we didnt want to come home #-o