Knipex also sells their "pliers wrenches" (in various sizes) that have smooth-faced jaws, intended for finished hardware. There are vids on Youtube or Knipex's website.
They will fit the flats on a nut, but not grip a round pipe/flange, etc, without some possible deforming from excess pressure, as the jaw faces are flat and parallel to each other (like adjustables).
The rubber covers for the cobra/alligator pliers will help grip a round pipe, etc, (Knipex part 58788) without marring. Chads toolbox has just about the lowest prices I've found, and flat rate shipping.
Knipex also has this
http://www.knipex.com/index.php?id=1216&L=1&page=group_detail&L=1&&parentID=1368&groupID=1493 , model 81 13 230 , pipe gripping pliers (with rubber pads).
RC